Delphi pre-build event not executing BEFORE compile

I'm busy automating our builds to include the svn revision number. We're using Delphi 2010. I added a pre-build event calling a batch file that injects the the svn revision number (read from the entries file in the .svn directory) and a specified version number into aVersionInfo.rc that is compiled with my project. The pre-build event looks like this:

call SetVersionInfo.bat 6 5 4

…and the batch file (hope someone finds this useful)…

@ECHO OFF
SETLOCAL
setLocal EnableDelayedExpansion

SET _myVar=0
FOR /F %%G in (.svn\entries.) DO (
IF !_myVar! LSS 3 SET /A _myVar+=1 & SET _svn_dir_rev=%%G
)

ECHO 1 VERSIONINFO > aVersionInfo.rc
ECHO. FILEVERSION %1,%2,%3,%_svn_dir_rev%   >> aVersionInfo.rc
ECHO. PRODUCTVERSION 1   >> aVersionInfo.rc
ECHO. FILEOS VOS__WINDOWS32   >> aVersionInfo.rc
ECHO. FILETYPE VFT_APP   >> aVersionInfo.rc
ECHO. BEGIN   >> aVersionInfo.rc
ECHO.   BLOCK "StringFileInfo"   >> aVersionInfo.rc
ECHO.   BEGIN   >> aVersionInfo.rc
ECHO.     BLOCK "080904b0"   >> aVersionInfo.rc
ECHO.     BEGIN   >> aVersionInfo.rc
ECHO.       VALUE "CompanyName","COMPANY\000"   >> aVersionInfo.rc
ECHO.       VALUE "FileDescription","APP\000"   >> aVersionInfo.rc
ECHO.       VALUE "FileVersion","%1.%2.%3.%_svn_dir_rev%\000"   >> aVersionInfo.rc
ECHO.       VALUE "InternalName","APP\000"   >> aVersionInfo.rc
ECHO.       VALUE "LegalCopyright","Copyright APP\000"   >> aVersionInfo.rc
ECHO.       VALUE "LegalTrademarks","APP\000"   >> aVersionInfo.rc
ECHO.       VALUE "OriginalFilename","APP.exe\000"   >> aVersionInfo.rc
ECHO.       VALUE "ProductName","APP\000"   >> aVersionInfo.rc
ECHO.       VALUE "ProductVersion,"1\000"   >> aVersionInfo.rc
ECHO.       VALUE "Comments","Compiled on %date% by %username%\000"   >> aVersionInfo.rc
ECHO.     END   >> aVersionInfo.rc
ECHO.   END   >> aVersionInfo.rc
ECHO.   BLOCK "VarFileInfo"   >> aVersionInfo.rc
ECHO.   BEGIN   >> aVersionInfo.rc
ECHO.     VALUE "Translation", 0x0809 1200   >> aVersionInfo.rc
ECHO.   END   >> aVersionInfo.rc
ECHO. END   >> aVersionInfo.rc
ENDLOCAL

The batch file does execute as part of a compile, aVersionInfo.rc is updated, aVersionInfo.res is recompiled, but for some reason the new res file is not used to compile the exe. It is, however, updated during a clean build or if I compile a second time. It seems the check for changes to the rc files takes place before the "pre"-build events are called. Which actually makes it a mid-build event. Or am I missing something?

I did try deleting the aVersionInfo.res file as another pre-build event, but then the compiler complains that this file is missing. Could it be that the

{$R 'aVersionInfo.res' 'aVersionInfo.rc'}

line is in the wrong place?