Hi Marc. I could be doing something wrong but it seems that the pre-linker batch runner isn't quite the right place to do this work.
If I touch the source file (I'm using a touch.exe in the batch file), it happens after the compile and leaves that source file 'dirty' as in always needing to be built (check mark in the left column of the files list in the project window). This could be considered ok, but isn't quite 'clean'.
If I delete the xxx.c.o file, the linker complains that it can't find the file in its NAMES list when it gets to the linking phase, which seems to make sense as I have just deleted the object file created by the compile process.
If I remember I can always just click in the left column of the files list and make that file dirty before a build...but automation is better than me remembering! 
Thanks,
Bill