Match manually entered receipts to invoices

When a customer orders something from us and chooses to prepay, we manually enter the receipt as un-applied cash and wait for the sale order to invoice and match it up manually after R42800.

New business requirement is to have these manually entered receipts automatically matched.

Our original design included a UBE to fetch the F4211 invoices and match them to a manually entered receipt where the sales order key was placed in the remark field. Then, once a match was found, use F03B13Z1 insert with R03B50 to match using R03B50D. well, F03b13z1 wants to make NEW receipts and