Purchase requisition events

[Hassine, Felix]

Hi all,
 
        We need to create 1 workflow instance when a purchase requisition is
created with the blocking flag on. Only 1 should be started, but the system
generates as many events as line items in the workflow. As a result, my
workflow may start several times, which is not the desired effect.
 
I have tested the "overall" release button in the customizing (Purchase Req
release Strategy), but then no event al all is then generated.
I have also attempted to create a "change" doc for change document class
"BANF" , but it works only for CHANGED status, not for CREATE.
 
Has anybody experienced the same problem ?
 
Thanks for any clue.
 
Felix Hassine