RE: credit notes applied to invoice
Hi nmirhan,
Using return orders to receive the items back from customer against an earlier invoiced sales order do not automatically settle the return order invoice (Credit note) against the original posted invoice. So the return order creation using "find sales order" and its further invoicing has no auto link to settle the original sales order posted invoice in standard AX.
The only thing that controls this is the automatic settlement in accounts receivable parameters for which you say that its setup to not to settle automatically.
So its difficult to say how you system is auto settling the return order invoice to original sales order invoice.
Can you kindly let us know how you judge that the invoices are settled with each other.
In standard the return order invoice and original sales order invoice will be available in "open transactions editing" and only after manual settlement they will be available at "closed transactions editing" in case automatic settlement is turned off from accounts receivable.
As Ludwig suggested it could be a system modification.