Hi,
Thank you, I'll check out the links you posted and see what I can find.
What I've found as I debugged up-and-back-out of the MV50AFz1-->userexit_save_document (where neither the HU data from the IDOC nor the updated VEKP records are yet available), is that my IDOC is processed like this...
SAPLBD20 include LBD20F0A (processes IDOCs)
Form IDOCS_PASS_TO_APPLICATION
(logic withiin reads tables to find my IDOC message type and calls corresponding function (which is BAPI_IDOC_INPUT1)
From that BAPI, the function is called for my IDOC type and eventually
BAPI_OUTB_DELIVERY_CONFIRM_DEC is called. This has the HU header passed to it, and contains the tracking number I need
I'm not sure how I will be able to get the HU data to be passed into the user exit I'm in, or if I will need to use another user exit, etc, and move my ecommerce process to a different user exit. I'll continue to debug and research.