I don't like th BDC option, but have tried with remove the 'completedocument check' whi1100 event and few otch avoids her events and it works.
But the BAPI does not populate any customer field in DFKKOP. I am adding to add the CI_FKKOP which is bascially all the Z fields in DFKKOP.
LS_EXTENSIONin-STRUCTURE = 'CI_FKKOP'.
LS_EXTENSIONin-VALUEPART1 = '50000000'.
APPEND LS_EXTENSIONin TO EXTENSIONin.