PO Receipt Mass Receipt BPM

I would like to create a BPM to create and exception if a PO receipt part has a standard cost of zero.

I created a BPM for the Receipt.UpdateMaster (from trace log) and I have that working just fine.

However, I have not figured out how to do the same thing for a Mass Receipt. The methods i have tried from the trace log are Reciept.PreUpdate and Receipt.CommitRcvDtl.

I added a BO widget to lookup the Partnumber with the PartCost table. however not sure where to go from here.

Any suggestions welcome.