Inventory value for customer owned items

We have a scenario where we purchase items for a customer and stock them in our inventory, ship, bill the customer as they are requested (we own the inventory a this point).  The customer tells us what to order based on their forecast.  If overstated forecast for a specific period, we bill the customer for items in stock but the product is maintained in our warehouse (physically).  We do not want the items to be included in any inventory valuation or other financial hit after they have been billed to the customer (who is now the owner).  They should eventually