How to define FIFO cost if On hand qty is 0 ?

Hello,

We have a business scenario where we want to define FIFO cost of an item which we do not receive against PO or manufacture in EBS.  In that case how can we define FIFO cost of the item ? I understand system create layer when we perform receipt or WIP transactions.

Business scenario is as follow :

1) Item A can be created by performed by doing WIP issue of item B (for which we have item cost defined as we receive against PO) and WIP negative issue of item C ( example qty -4) . Is this case how can we define FIFO cost of item C as it is replenished to inventory?