Cannot add promotional item to drop ship order. Message that item is not purchase enabled

I have a promotional item (its an allowance/discount) that is added to an order at booking time.  We have used it for years and works fine.  We have several types of drop ship orders - transaction types - which are defined the same, with same line workflow.  This modifier works on one type of drop ship order.  Now we want to use it on another drop ship order type.  These work out of separate inventory organizations.

We are getting the following message and the order cannot be booked:  "Item xxx is not purchase enabled in organization yyy'.

This is true.  But we do not want to purchase a discount item -- it should not go on the requisition or PO.  It should flow to Awaiting Fulfillment.