diff --git a/Modules/AddExternalProject.cmake b/Modules/AddExternalProject.cmake
index 9e14bd24f..5fd6df046 100644
--- a/Modules/AddExternalProject.cmake
+++ b/Modules/AddExternalProject.cmake
@@ -36,12 +36,78 @@ function(get_configure_build_working_dir name working_dir_var)
 endfunction(get_configure_build_working_dir)
 
 
+function(get_configure_command_id name cfg_cmd_id_var)
+  get_target_property(cmd ${name} AEP_CONFIGURE_COMMAND)
+
+  if(cmd STREQUAL "")
+    # Explicit empty string means no configure step for this project
+    set(${cfg_cmd_id_var} "none" PARENT_SCOPE)
+  else()
+    if(NOT cmd)
+      # Default is "use cmake":
+      set(${cfg_cmd_id_var} "cmake" PARENT_SCOPE)
+    else()
+      # Otherwise we have to analyze the value:
+      if(cmd MATCHES "/configure$")
+        set(${cfg_cmd_id_var} "configure" PARENT_SCOPE)
+      else()
+        if(cmd MATCHES "cmake")
+          set(${cfg_cmd_id_var} "cmake" PARENT_SCOPE)
+        else()
+          if(cmd MATCHES "config")
+            set(${cfg_cmd_id_var} "configure" PARENT_SCOPE)
+          else()
+            set(${cfg_cmd_id_var} "unknown:${cmd}" PARENT_SCOPE)
+          endif()
+        endif()
+      endif()
+    endif()
+  endif()
+endfunction(get_configure_command_id)
+
+
 function(add_external_project_download_command name)
   set(added 0)
   get_external_project_directories(base_dir build_dir downloads_dir install_dir
     sentinels_dir source_dir tmp_dir)
 
 
+  if(NOT added)
+  get_target_property(cmd ${name} AEP_DOWNLOAD_COMMAND)
+  if(cmd STREQUAL "")
+    # Explicit empty string means no download step for this project
+    add_custom_command(
+      OUTPUT ${sentinels_dir}/${name}-download
+      COMMAND ${CMAKE_COMMAND} -E touch ${sentinels_dir}/${name}-download
+      WORKING_DIRECTORY ${sentinels_dir}
+      COMMENT "No download step for '${name}'"
+      )
+    set(added 1)
+  else()
+    if(cmd)
+      set(args "")
+      get_target_property(download_args ${name} AEP_DOWNLOAD_ARGS)
+      if(download_args)
+        set(args "${download_args}")
+        separate_arguments(args)
+      endif()
+
+      add_custom_command(
+        OUTPUT ${sentinels_dir}/${name}-download
+        COMMAND ${cmd} ${args}
+        COMMAND ${CMAKE_COMMAND} -E touch ${sentinels_dir}/${name}-download
+        WORKING_DIRECTORY ${downloads_dir}
+        COMMENT "Performing download step for '${name}'"
+        )
+      set(added 1)
+    else()
+      # No explicit DOWNLOAD_COMMAND property. Look for other properties
+      # indicating which download method to use in the logic below...
+    endif()
+  endif()
+  endif()
+
+
   if(NOT added)
   get_target_property(cvs_repository ${name} AEP_CVS_REPOSITORY)
   if(cvs_repository)
@@ -275,13 +341,21 @@ function(add_external_project_build_command name)
       DEPENDS ${sentinels_dir}/${name}-configure
       )
   else()
+    get_configure_command_id(${name} cfg_cmd_id)
+
     if(NOT cmd)
-      set(cmd ${CMAKE_COMMAND})
+      set(cmd make)
+      if(cfg_cmd_id STREQUAL "cmake")
+        set(cmd ${CMAKE_COMMAND})
+      endif()
     endif()
 
     get_target_property(args ${name} AEP_BUILD_ARGS)
     if(NOT args)
-      set(args --build ${working_dir} --config ${CMAKE_CFG_INTDIR})
+      set(args)
+      if(cfg_cmd_id STREQUAL "cmake")
+        set(args --build ${working_dir} --config ${CMAKE_CFG_INTDIR})
+      endif()
     endif()
 
     add_custom_command(
@@ -312,13 +386,24 @@ function(add_external_project_install_command name)
       DEPENDS ${sentinels_dir}/${name}-build
       )
   else()
+    get_configure_command_id(${name} cfg_cmd_id)
+
     if(NOT cmd)
-      set(cmd ${CMAKE_COMMAND})
+      set(cmd make)
+      if(cfg_cmd_id STREQUAL "cmake")
+        set(cmd ${CMAKE_COMMAND})
+      endif()
     endif()
 
     get_target_property(args ${name} AEP_INSTALL_ARGS)
     if(NOT args)
-      set(args --build ${working_dir} --config ${CMAKE_CFG_INTDIR} --target install)
+      set(args)
+      if(cfg_cmd_id STREQUAL "cmake")
+        set(args --build ${working_dir} --config ${CMAKE_CFG_INTDIR} --target install)
+      endif()
+      if(cfg_cmd_id STREQUAL "configure")
+        set(args "install")
+      endif()
     endif()
 
     add_custom_command(
@@ -339,123 +424,101 @@ function(add_CMakeExternals_target)
       sentinels_dir source_dir tmp_dir)
 
     add_custom_command(
-      OUTPUT ${tmp_dir}
+      OUTPUT ${sentinels_dir}/CMakeExternals-directories
       COMMAND ${CMAKE_COMMAND} -E make_directory ${build_dir}
       COMMAND ${CMAKE_COMMAND} -E make_directory ${downloads_dir}
       COMMAND ${CMAKE_COMMAND} -E make_directory ${install_dir}
       COMMAND ${CMAKE_COMMAND} -E make_directory ${sentinels_dir}
       COMMAND ${CMAKE_COMMAND} -E make_directory ${source_dir}
       COMMAND ${CMAKE_COMMAND} -E make_directory ${tmp_dir}
+      COMMAND ${CMAKE_COMMAND} -E touch ${sentinels_dir}/CMakeExternals-directories
+      COMMENT "Creating CMakeExternals directories"
     )
 
     add_custom_target(CMakeExternals ALL
-      DEPENDS ${tmp_dir}
+      DEPENDS ${sentinels_dir}/CMakeExternals-directories
     )
   endif()
 endfunction(add_CMakeExternals_target)
 
 
+function(is_known_aep_property_key key result_var)
+  set(${result_var} 0 PARENT_SCOPE)
+
+  if(key MATCHES "^BUILD_ARGS|BUILD_COMMAND|CONFIGURE_ARGS|CONFIGURE_COMMAND|CONFIGURE_DIR|CVS_REPOSITORY|CVS_MODULE|CVS_TAG|DEPENDS|DOWNLOAD_ARGS|DOWNLOAD_COMMAND|DIR|INSTALL_ARGS|INSTALL_COMMAND|SVN_REPOSITORY|SVN_TAG|TAR|TAR_URL|TGZ|TGZ_URL$"
+  )
+    #message(STATUS "info: recognized via MATCHES - key='${key}'")
+    set(${result_var} 1 PARENT_SCOPE)
+  else()
+    message(STATUS "warning: is_known_aep_property_key unknown key='${key}'")
+  endif()
+endfunction(is_known_aep_property_key)
+
+
 function(add_external_project name)
   get_external_project_directories(base_dir build_dir downloads_dir install_dir
     sentinels_dir source_dir tmp_dir)
 
+
+  # Ensure root CMakeExternals target and directories are created.
+  # All external projects will depend on this root CMakeExternals target.
+  #
   add_CMakeExternals_target()
 
+
+  # Add a custom target for the external project and make its DEPENDS
+  # the output of the final build step:
+  #
   add_custom_target(${name} ALL
     DEPENDS ${sentinels_dir}/${name}-install
   )
   set_target_properties(${name} PROPERTIES AEP_IS_EXTERNAL_PROJECT 1)
+  add_dependencies(${name} CMakeExternals)
 
-  # Loop over ARGN by 2's extracting key/value pairs from
-  # the non-explicit arguments to the function:
+
+  # Transfer the arguments to this function into target properties for the
+  # new custom target we just added so that we can set up all the build steps
+  # correctly based on target properties.
+  #
+  # Loop over ARGN by 2's extracting key/value pairs from the non-explicit
+  # arguments to this function:
   #
   list(LENGTH ARGN n)
   set(i 0)
   while(i LESS n)
     math(EXPR j ${i}+1)
+
     list(GET ARGN ${i} key)
     list(GET ARGN ${j} value)
-    #message(STATUS "  ${key}='${value}'")
 
-    if(key STREQUAL "BUILD_ARGS")
-      set_target_properties(${name} PROPERTIES AEP_BUILD_ARGS "${value}")
-    endif()
+    is_known_aep_property_key("${key}" is_known_key)
 
-    if(key STREQUAL "BUILD_COMMAND")
-      set_target_properties(${name} PROPERTIES AEP_BUILD_COMMAND "${value}")
-    endif()
-
-    if(key STREQUAL "CONFIGURE_ARGS")
-      set_target_properties(${name} PROPERTIES AEP_CONFIGURE_ARGS "${value}")
-    endif()
-
-    if(key STREQUAL "CONFIGURE_COMMAND")
-      set_target_properties(${name} PROPERTIES AEP_CONFIGURE_COMMAND "${value}")
-    endif()
-
-    if(key STREQUAL "CONFIGURE_DIR")
-      set_target_properties(${name} PROPERTIES AEP_CONFIGURE_DIR "${value}")
-    endif()
-
-    if(key STREQUAL "CVS_REPOSITORY")
-      set_target_properties(${name} PROPERTIES AEP_CVS_REPOSITORY "${value}")
-    endif()
-
-    if(key STREQUAL "CVS_MODULE")
-      set_target_properties(${name} PROPERTIES AEP_CVS_MODULE "${value}")
-    endif()
-
-    if(key STREQUAL "CVS_TAG")
-      set_target_properties(${name} PROPERTIES AEP_CVS_TAG "${value}")
-    endif()
-
-    if(key STREQUAL "DEPENDS")
-      add_dependencies(${name} ${value})
-    endif()
-
-    if(key STREQUAL "DIR")
-      set_target_properties(${name} PROPERTIES AEP_DIR "${value}")
-    endif()
-
-    if(key STREQUAL "INSTALL_ARGS")
-      set_target_properties(${name} PROPERTIES AEP_INSTALL_ARGS "${value}")
-    endif()
-
-    if(key STREQUAL "INSTALL_COMMAND")
-      set_target_properties(${name} PROPERTIES AEP_INSTALL_COMMAND "${value}")
-    endif()
-
-    if(key STREQUAL "SVN_REPOSITORY")
-      set_target_properties(${name} PROPERTIES AEP_SVN_REPOSITORY "${value}")
-    endif()
-
-    if(key STREQUAL "SVN_TAG")
-      set_target_properties(${name} PROPERTIES AEP_SVN_TAG "${value}")
-    endif()
-
-    if(key STREQUAL "TAR")
-      set_target_properties(${name} PROPERTIES AEP_TAR "${value}")
-    endif()
-
-    if(key STREQUAL "TAR_URL")
-      set_target_properties(${name} PROPERTIES AEP_TAR_URL "${value}")
-    endif()
-
-    if(key STREQUAL "TGZ")
-      set_target_properties(${name} PROPERTIES AEP_TGZ "${value}")
-    endif()
-
-    if(key STREQUAL "TGZ_URL")
-      set_target_properties(${name} PROPERTIES AEP_TGZ_URL "${value}")
+    if(is_known_key)
+      if(key STREQUAL "DEPENDS")
+        if(NOT value STREQUAL "")
+          add_dependencies(${name} ${value})
+        else()
+          message(STATUS "warning: empty DEPENDS value in add_external_project")
+        endif()
+      else()
+        set_target_properties(${name} PROPERTIES AEP_${key} "${value}")
+      endif()
+    else()
+      message(SEND_ERROR "error: unknown add_external_project key with name='${name}' key='${key}' value='${value}'")
     endif()
 
     math(EXPR i ${i}+2)
   endwhile()
 
+
+  # Set up custom build steps based on the target properties.
+  # Each step depends on the previous one.
+  #
+  # The target depends on the output of the final step.
+  # (Already set up above in the DEPENDS of the add_custom_target command.)
+  #
   add_external_project_download_command(${name})
   add_external_project_configure_command(${name})
   add_external_project_build_command(${name})
   add_external_project_install_command(${name})
-
-  add_dependencies(${name} CMakeExternals)
 endfunction(add_external_project)
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index c894037d1..00fffc9b4 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -16,23 +16,64 @@ set(prefix "${install_dir}")
 #
 include("${CMAKE_CURRENT_SOURCE_DIR}/TryCheckout.cmake")
 
-try_cvs_checkout(
-  ":pserver:anonymous:cmake@www.cmake.org:/cvsroot/CMake"
-  "CMake/Tests/Tutorial/Step1"
-  "${CMAKE_CURRENT_BINARY_DIR}/TryCheckout/TutorialStep1"
-  can_use_cvs
-  )
+if(NOT DEFINED can_use_cvs)
+  try_cvs_checkout(
+    ":pserver:anonymous:cmake@www.cmake.org:/cvsroot/CMake"
+    "CMake/Tests/Tutorial/Step1"
+    "${CMAKE_CURRENT_BINARY_DIR}/TryCheckout/TutorialStep1"
+    can_use_cvs
+    )
+  set(can_use_cvs ${can_use_cvs} CACHE STRING "Was try_cvs_checkout successful?")
+endif()
 
-try_svn_checkout(
-  "http://gdcm.svn.sourceforge.net/svnroot/gdcm/trunk/Utilities/gdcmmd5"
-  "${CMAKE_CURRENT_BINARY_DIR}/TryCheckout/gdcmmd5"
-  can_use_svn
-  )
+if(NOT DEFINED can_use_svn)
+  try_svn_checkout(
+    "http://gdcm.svn.sourceforge.net/svnroot/gdcm/trunk/Utilities/gdcmmd5"
+    "${CMAKE_CURRENT_BINARY_DIR}/TryCheckout/gdcmmd5"
+    can_use_svn
+    )
+  set(can_use_svn ${can_use_svn} CACHE STRING "Was try_svn_checkout successful?")
+endif()
 
 message(STATUS "can_use_cvs='${can_use_cvs}'")
 message(STATUS "can_use_svn='${can_use_svn}'")
 
 
+# Empty projects that test all the known add_external_project argument key words:
+#
+set(proj MinimalNoOpProject)
+add_external_project(${proj}
+  BUILD_COMMAND ""
+  CONFIGURE_COMMAND ""
+  DOWNLOAD_COMMAND ""
+  INSTALL_COMMAND ""
+)
+
+set(proj EmptyNoOpProject)
+add_external_project(${proj}
+  BUILD_ARGS ""
+  BUILD_COMMAND ""
+  CONFIGURE_ARGS ""
+  CONFIGURE_COMMAND ""
+  CONFIGURE_DIR ""
+  CVS_REPOSITORY ""
+  CVS_MODULE ""
+  CVS_TAG ""
+  DEPENDS "MinimalNoOpProject"
+  DIR ""
+  DOWNLOAD_ARGS ""
+  DOWNLOAD_COMMAND ""
+  INSTALL_ARGS ""
+  INSTALL_COMMAND ""
+  SVN_REPOSITORY ""
+  SVN_TAG ""
+  TAR ""
+  TAR_URL ""
+  TGZ ""
+  TGZ_URL ""
+)
+
+
 # Local DIR:
 #
 set(proj TutorialStep5-Local)
@@ -70,7 +111,7 @@ add_external_project(${proj}
 
 set(proj TutorialStep1-LocalNoDirTGZ)
 add_external_project(${proj}
-  TGZ "${CMAKE_CURRENT_SOURCE_DIR}/Step1.tgz"
+  TGZ "${CMAKE_CURRENT_SOURCE_DIR}/Step1NoDir.tgz"
   CONFIGURE_ARGS "\"-DCMAKE_INSTALL_PREFIX:PATH=${prefix}\" -G \"${CMAKE_GENERATOR}\" \"${source_dir}/${proj}\""
   INSTALL_COMMAND ""
 )
@@ -91,12 +132,13 @@ add_external_project(${proj}
 if(can_use_cvs)
   # CVS by date stamp:
   #
-  set(proj KWStyle-20081201)
+  set(proj TutorialStep1-20081201)
   add_external_project(${proj}
-    CVS_REPOSITORY ":pserver:anoncvs@public.kitware.com:/cvsroot/KWStyle"
-    CVS_MODULE "KWStyle"
+    CVS_REPOSITORY ":pserver:anonymous:cmake@www.cmake.org:/cvsroot/CMake"
+    CVS_MODULE "CMake/Tests/Tutorial/Step1"
     CVS_TAG "-D\;2008-12-01 01:00:00 UTC"
     CONFIGURE_ARGS "\"-DCMAKE_INSTALL_PREFIX:PATH=${prefix}\" -G \"${CMAKE_GENERATOR}\" \"${source_dir}/${proj}\""
+    INSTALL_COMMAND ""
   )
 
   # CVS by tag:
@@ -112,12 +154,19 @@ if(can_use_cvs)
 
   # Live CVS / HEAD (no CVS_TAG):
   #
-  set(proj TutorialStep1-CVSHEAD)
+  set(proj KWStyle-CVSHEAD)
   add_external_project(${proj}
-    CVS_REPOSITORY ":pserver:anonymous:cmake@www.cmake.org:/cvsroot/CMake"
-    CVS_MODULE "CMake/Tests/Tutorial/Step1"
+    CVS_REPOSITORY ":pserver:anoncvs@public.kitware.com:/cvsroot/KWStyle"
+    CVS_MODULE "KWStyle"
     CONFIGURE_ARGS "\"-DCMAKE_INSTALL_PREFIX:PATH=${prefix}\" -G \"${CMAKE_GENERATOR}\" \"${source_dir}/${proj}\""
-    INSTALL_COMMAND ""
+    DEPENDS "EmptyNoOpProject"
+    DEPENDS "TutorialStep5-Local"
+    DEPENDS "TutorialStep1-LocalTAR"
+    DEPENDS "TutorialStep1-LocalNoDirTAR"
+    DEPENDS "TutorialStep1-LocalTGZ"
+    DEPENDS "TutorialStep1-LocalNoDirTGZ"
+    DEPENDS "TutorialStep1-20081201"
+    DEPENDS "kwsys-from-CMake-2-6-2"
   )
 endif()
 
@@ -162,7 +211,7 @@ enable_testing()
 
 # Use these as input to the KWStyle tests:
 #
-set(kwstyleXmlFile "${source_dir}/KWStyle-20081201/Testing/Data/0001-KWStyleConfiguration.kws.xml")
+set(kwstyleXmlFile "${source_dir}/KWStyle-CVSHEAD/Testing/Data/0001-KWStyleConfiguration.kws.xml")
 set(header "${install_dir}/include/TutorialConfig.h")
 
 
@@ -187,14 +236,14 @@ add_test(TutorialStep1-LocalNoDirTGZ-BuildTreeTest
   "${build_dir}/TutorialStep1-LocalNoDirTGZ/Tutorial" 9)
 
 if(can_use_cvs)
-  add_test(KWStyle-20081201-BuildTreeTest
-    "${build_dir}/KWStyle-20081201/KWStyle" -xml "${kwstyleXmlFile}" "${header}")
+  add_test(TutorialStep1-20081201-BuildTreeTest
+    "${build_dir}/TutorialStep1-20081201/Tutorial" 4)
 
   add_test(kwsys-from-CMake-2-6-2-BuildTreeTest
     "${build_dir}/kwsys-from-CMake-2-6-2/kwsysTestProcess" 1)
 
-  add_test(TutorialStep1-CVSHEAD-BuildTreeTest
-    "${build_dir}/TutorialStep1-LocalNoDirTGZ/Tutorial" 4)
+  add_test(KWStyle-CVSHEAD-BuildTreeTest
+    "${build_dir}/KWStyle-CVSHEAD/KWStyle" -xml "${kwstyleXmlFile}" "${header}")
 endif()
 
 if(can_use_svn)