foreign currency revaluation (on dynamics 365!)


I'm in some trouble and hope you can help me.One of my clients runs a number of foreign currencies. Our problem is that from the time of issuing an order to the moment of payment there is a period and the currency rates change.So I'm looking for a way to "re-evaluate" the re-order on the payment day to adjust the payment to the order. I found no logical and easy way to do this in dynamics 365 (and it's important to emphasize! The product is dynamics 365 and not AX or Finance and Operations)

For example:

Order as of January 1, 2019 for $ 100 according to base currency 500

Payment for this order (from January 01, 2019) $ 100 Payment in base currency 400 (due to exchange rate change)

My client's books have a 100 gap in base currency (a serious problem). I am looking for a way to make revaluation to the order at the pay rate (which is important for a base currency adjustment).

Any Offer Welcome! I'm really at a loss.