This morning I downloaded Creator 4.1 and went to play with the post build capability.
After working with it for less than an hour I wasted about an hour trying to post my results here. Kept getting access denied etc. Tried some simple posts (and deleted them) so it may have been choking on some of my content.
Attached is a PDF with the results of my efforts. Please review and let me know if it helps you get started.
On reviewing this the perl script doesn't look logically the same as the user command operation. I will do some more testing and advise.