1. User enters Sales Order → goes to item screen.

2. User enters Material + Quantity.

3. SAP validates item → calls USEREXIT_CHECK_VBAP.

   • Your enhancement runs.

   • If xvbap-kwmeng < 10, show error/warning.

   • If OK → continue.

4. User clicks Save.

5. SAP calls USEREXIT_SAVE_DOCUMENT_PREPARE → do final checks.

6. SAP calls USEREXIT_SAVE_DOCUMENT → write any custom data.

7. Standard commit → sales order saved in tables (VBAK, VBAP, VBEP, etc.).

FORM userexit_move_field_to_vbak.

“””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””””$”$\SE:(4) Form USEREXIT_MOVE_FIELD_TO_VBAK, End                                                                                                             A
*$*$-Start: (4)———————————————————————————$*$*
ENHANCEMENT 1  ZAUG_IMP_EN.    “active version
*
  if sy–uname =’77USER67′.
  MESSAGE ‘Enhancement trigger’ type ‘I’.
  endif.

ENDENHANCEMENT.
ENHANCEMENT 1  ZSEP_IMP_ENH.    “active version

ENDENHANCEMENT.
*$*$-End:   (4)———————————————————————————$*$*
ENDFORM.

once you implement this code logic in the explicit enhancement and try to do any create and modify operation you will get a message.