OS Commerce Modifications

I have a version of oscommerce with various mods - ie cross sell, easy populate, etc. In addition to this, I have a calculator that spits out a value for a users item. It says the amount of money they would be paid if they sold it, and the amount it would be if they traded. This is currently completely separate from the oscommerce website right now, but what I need it to do is to take the values and integrate into the system. If a user is going to sell their item, it will take them to create an account or login using the oscommerce system of course, and it will give them details when they process the order as to how they would ship the item. If they choose to trade, it would store the value of their item in the shopping cart, and would deduct the price they would owe from what they want to trade in. The backend would still display the usual oscommerce order features, but would have a spot that gives all details of the item the user is selling them. I would need the modifications of os commerce to be cleanly documented, so I can take that code and implement it myself, but if I cannot do it, you would need to go ahead and implement it into the development site for me. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform php/mysql