X-Cart Shipping Modifications

We need UPS Real Time (including FedEx and USPS) shipping calculations to be more accurate with our online store that is based upon X-Cart's php shopping cart, version 4.x.x. 1) On each item in the store we need to enter item dimensions (length - height - width). These need to be three separate entry boxes for each item in the product section of the cart. The cart needs to use these dimensions to calculate total package dimensions and communicate this to the various Rate Servers so as to return accurate shipping rates. The database currently has these fields but they are not being utilized. 2) Certain items need to be specified as a single package in the product details so that the real time shipping calculations show this single item will be shipped as one box. With the dimensions, weight, and selection of "Single Package" within the product details, when the customer's order info is sent to the shipping rate server it will know that this item is a single package. Other items added to the order could be either single packages or combined items into a second or third package. The Rate Server would be able to return shipping calculations for one or more packages based upon this order info. 3) A rollover level needs to be applied by WEIGHT and DIMENSION so that when combined items added to each customer's order exceed a weight limit or dimensional limit a new package reference is sent to the rate servers. These need to be set as admin adjustable figures per item in the store. Rollovers would need to be ignored on items that have specific shipping charges specified in the product manager, or have been selected already as a Single Package (item #2 above). The above features are already built into the UPS Tools, so it is just a matter of coding in the calls to the UPS Rate Server (as X-Cart already does now on a limited basis with just weight), adding entry boxes into the product details, placing the management of these features into the shipping section of the site, and adding the corresponding tables to the database are part of this project. X-Cart devs have not fully supported FedEx within the cart. But, the above modifications must be able to work with ALL shipping agencies (UPS, FedEx, USPS, DHL, etc) as long as the page that holds the script(s) that calls to the rate servers has coding available for each shipper. Please contact me if you require more information. You should be extremely familiar with the various shipping modules, mySQL databases, php coding, and smarty tags. Security and Script Speed and Accuracy is a high priority.