Hi Jason,
Please refer to the following article for the details of creating IDOC.
Regarding which segments should be post, I guess this should be answered from application side.
If you met any errors when creating the IDOC, please give us the detailed information so we can
analyze further. Please let me know the error message, which message type you are using, how
you configured the partner profile, if you have used any event type linkage, how to recreate the error with step-by-step guide.
Step by Step procedure for creation of IDOC - Wiki - SCN Wiki
Best regards
Helen