First of all a bug:
You cannot use the enter key when editing your Post or Pre Compile Script. If you use it the dialog will close.
Secondly the suggestion
Make some sort of Pre-Pre Compile Script. I currently store the compiled u files in a different directory for Defence Alliance. Before I compile I want to move them from %UTPATH%DASystem to %UTPATH%System. If I do this using a pre compile script it won't delete the files that need to be recompiled.
The post compile script works fine