Workflow Events for transaction FP09

Hi All,

The requirement is to trigger a workflow when the user posts a return lot through transaction FP09. I used the event trace but this transaction does not fire any event when we post a Return Lot. I tried to find some user exits but with no luck. Is it possible to fire an event when a field in the database table changes ? The table is a standard table(DFKKRK) and the field is STARS. When this field holds a number 5 then it depicts that the document is posted.

Best Regards,

Sudhi