EDI for purchasing - have you done it?

Has anyone used Lanhams EDI Add-On as the basis of developing purchasing EDI.

Currently EDI is only designed to work on the Sales Side. The biggest issue is Receiving a VCendor invoice, and then reconciling it back to the Originaly sent 850.

I am thinking the best solution is to import the 810 into a Purchase Invoice document (T38+T39) and then reconcile that back to the original Purchase Order.

Since I know that the company are going to have to do development I posted it here, but it could just as well have been in the End User Quesitons.