I agree i wear -4.5 glasses. But trust me, i activated this implementation and i saw through my glasses and kind of double checked after your persistent suggestion on activation 
Anyways, problem is that BAdI ME_PROCESS_PO_CUST is not multiple use type. So gotta see, how these guys solved it:
http://scn.sap.com/thread/1363372
Will let know on how it goes.
Regards,
KS