I am trying to get LIV via EDI working. The incoming INVOIC02 IDOCS mark an error when processing: there is no PO item in the ZEILE field of E1EDP02-001. I thought I could use EXIT_SAPLIEDI_011 to get the PO item number determined and to get this problem solved. But I cannot see where the exit is called during the LIV process. Does anyone know where EXIT_SAPLIEDI_011 is called and how I can test this?