Backorder sales and purchase - add suffix to Invoice number (or our PO number), backorder report

We would desperately like an option in the sales and purchases preferences to automatically add a sequential suffix to the original sales invoice number (or purchase order number for purchases) that increases sequentially with each backorder related to the one original order, eg -1, -2, -3 or-A, -B, -C, or BO1, BO2, BO3 etc

Allocating a new/unique/unrelated invoice number (or PO number) does not work for us as this code is the ONLY way in MYOB to link a backorder to the original order for sales and purchases.

The ability to produce back order reports would also be useful (for sales and purchases) - showing original inv/PO, original date, and what is left to send/receive.

Please vote!