C# library for updating shipment tracking info in Amazon

This project is for building C# library which allows updating of shipment tracking information in Amazon using either Amazon API (preferred solution) or HTML parsing and form posting. I'm not sure where the to draw the line between amazon web services and their online store. We currently have a order management system, which process orders from different sources (e.g. ebay, amazon, etc.) when an order is being shipped, we get a tracking number from the carrier to be able to track the shipment, this information needs to be updated in the site from which the order has been received. currently - our system knows how to update this information in paypal, and we would like o be able to update this information in amazon as well. what we require is a c# code which accepts an amazon transaction identifier, a tracking number, a carrier and account information and sets this information in amazon.