If the problem is with the inbound idoc processing.
Go to WE20 transaction, respective partner profile --> Inbound parameters ---> message type and display.
Under the Inbound options tab, double click on process code, the function module mentioned in Identification is used to process the inbound idoc.
Place a break point inside the function module, recreate the idoc using the transaction WE19 and debug the code to find it.
Regards,
TP