Modifying Product Availability for Zen Cart Store

We have added a Date Available module for a Zen Cart web store. This allows the store to take back orders for products not currently in stock. These products are set with an incoming due date. However we want to be able to limit the number of orders we receive for a particular product. So for example if we are expecting 5 stock of a new TV we want the pre-order option to only allow 5 orders. We believe there is only one file that needs modification, the details of which can be found in the advanced details. ## Deliverables Additional info is attached. Please read before posting your bid.