IntraStat IDEP Report FOB

Evidently there is a bug in the IntraStat IDEP Report that Epicor has acknowledged and have assured us they will fix in the next release where even though the FOB is present in the report data definition it doesn’t pull the data through to the SSRS report. We have verified with a BAQ that there is actually data in this field. I’m attempting a workaround (instead of having to create an entirely new report from the BAQ) in which I’m trying to link the InvcHead to IStatTrn and pull the FOB from the InvcHead. I must be doing something wrong though as every time I create the relationship and run the report it errors out. The relationship is as follows:
Parent=IStatTrn, Child=InvcHead, Key=SourceIdx, Relationship fields=Company & InvoiceNum. Does anyone see any glaring mistakes here?