osCommerce - Variation SKU

Hello, I am currently in the process of developing an ecommerce website for the running/walking store I work for. We have been selling on [login to view URL] for some time and would like to also sell our inventory on our website. We decided, probably prematurely, that we liked a certain osCommerce template so went with osCommerce for our shopping cart. Because we sell our inventory in store, on amazon, and now on the website we will be needing to keep our inventory in-sync across channels. To do this we have been using Webgility's ECC as a bridge between our ecommerce channels and our master database file (Quickbooks POS). ECC has built-in osCommerce functionality and we have added the proper module to our osCommerce store for linking with ECC. Our issue is how osCommerce does not track stock at the attribute level. We are primarily a shoe store so we will have various sizes and colors of any given shoe that will need to be consolidated under one product--and the quantities of each variation needs to be tracked. Each child product/variation will need to have a SKU assigned to it. It would also be nice if there was another field added for UPC. We thought that installing the osCommerce contribution "QTpro" would of solved this--but QTpro does not assign a SKU to each product variation. It is important that our inventory sync software "Webgility ECC" is able to see each product variation as a unique item for keeping the on-hand quantity correct. I suspect a modification of the contribution QTpro is in order--but I do not see anyone who has done this. See youtube video here for what it is I think I need--[login to view URL] The important work I need is the ability to add SKU's to each product variation. Example; Nike Zoom Structure+ 16 (parent/main item) (no SKU needed for parent item) Size:10.5 - Color: Grey/Blue - SKU - 001 Size: 11.0 - Color: Grey/Blue - SKU - 002 Size: 11.5 - Color: Grey/Blue - SKU - 003 I know that this isn't the clearest of explanations, but please ask me specific questions about the project and I can probably answer them. Price is negotiable as long as you are confident that you can deliver 100% the solution I am looking for. Thanks for your time!