RMA negative commitments

When we create an RMA (R8 type) and take the Form Exit to the Sales Ledger and select a line, and bring it back into P40051, we have noticed that it uses the locations from the sales order instead of the locations from the RMA Defaults.  This is causing the inventory to show, in summary availability, that there is 0 onhand for the lot/location, with a negative committed amount for the amount being returned, which in turn causes a positive availability for that same amount.  The pick program (R42520) will then pick this lot and move the order to 550,