Ebay store synchronization

I have a customized commerce site which i want to create an addon for. This addon software will read my database tables and synchronize with an ebay store. As I add product information including inventory to my database tables, the addon software will synchronize the information to ebay. When someone purchases an item in my ebay store, the inventory will then be updated back to my commerce application. ( basically product information will be pushed out to ebay - but ebay will need to update inventory information back to my commerce site ) Developer will need to create a test store on ebay ( [login to view URL] ). I will provide the database tables (mysql) that will need to be synchronized. The addon will need to be written in php. I will create a cron job that will execute the addon script(s) to synchronize this information. The script will need to record into a database log table all information necessary for debugging purposes. I'm attaching code that does a lot of what i'm looking for but which was written as an addon to osCommerce. Developer will be able to use 'much' of the code already here. A lot of it is very straightforward code. Final product will need to include all database tables and php scrips including 'detail' instruction document explaining how to create and configure the ebay store to make this work with the new code. I will send database structure of tables and any other information to winning bidder.