This article explains how the customer product ID is used on EDI 810 file.
Invoices created for EDI Trading Partners in Acctivate can be exported into an 810 file using the EDI Manager (see the EDI Processing webinar). The 810 file takes data related to the Invoice and arranges it into a specific structure (see the 810 article). One of the fields included in the 810 is the Trading Partner Item ID, found in position 4 of the I row in the 810 file. Before Acctivate 10.1, this field only populated data if the Invoice was related to a Sales Order created using an EDI 850 file (again I row, position 4). However, Acctivate supports 810 file creation for customers related to EDI Trading Partners, even if the related Sales Order was not created using an 850 file, so Acctivate 10.1 introduces an enhancement which changes how the data in this field is populated.
First, Acctivate will look for that Buyer Product ID found in the 850 file, the way that it always has. If that field contains no data, or if no 850 is related to the Sales Order, Acctivate will next use the Customer Product ID configured in the Customer Window (see the Customer Product ID help article). If no Customer Product ID is configured for that Product/Customer, Acctivate will next use the Product ID in the 810 file.