From a standard SAP process, the instruction key that is updated in vendor master (LFA1-DTAWS) is captured in to REGUH-DTAWS when F110 or RFF110S is executed. As a next step when SAPFPAYM ( t code FBPM) is executed, this gets populated in the XML file.
For some reasons that does not seem to happen for me. I have identified SAP notes 2106391 ( includes 1574937 &1779966) for this issue.
Did some one come across a similar issue like this. Does this notes fix the issue?