GetNewCustCnt, Column 'Ship To' does not belong to table CustCnt

I am trying to sort out the usage of the GetNewCustCnt method using the WCF-Tester app. No matter what I try, the method is failing with Column 'Ship To' does not belong to table CustCnt. I see that ShipTo is it's own table, but I don't see how to associate the two with this method. Any ideas?

Tim