I have a supplier XYZ who is originally set up to be paid in CDN dollars. The supplier invoices in US dollars. I convert the invoice amount in US dollars to CDN dollars (I have a fixed exhange rate). When I receive payment from CDN customers in CDN dollars - I pay the supplier and depending on the exchange, it will result in a foreign exchange gain or loss - which will be cleared and posted to a foreigh exchange account.

Recently, there were changes: I placed an order to the supplier. The Proforma Invoice is in US dollars. I made a prepayment to the supplier in CDN dollars. My customer decides to pay in US dollars. I set up the supplier to be paid in US dollars - I named the supplier XYZ USD. I post the entire invoice in US dollars. I pay the balance of the invoice in US dollars. But now, I have a prepayement in XYZ and balance in XYZ USD. How do I clear this up?

Thanks