Credit note or debit note on obsolete stocking type item

I know it's not possible to enter sales/purchase order on obsolete items (STKT='O'). Typically, when you have sold all of an item with stocking type 'U', you would change the stocking type to O.

In this case, you can not accept any sales / purchase order entry. But for non stock order (financial document). I would like be able to enter a non stock credit note (Inventory interface line type definition = 'D' and reverse Sign = 'Y'). Our customer may ask to receive a credit note two years after the item has been ended. We are obliged to change the item branch plant stocking type to 'U' to allow us to enter the order.