Create a shipping module for CS-Cart 3.x

I am starting a CS-Cart based store in Brazil and I need a freelancer to write a shipping module for Brazil's Correios. Correios is the main postal service in Brazil. They do provide an XML-based webservice with which you'll be able to retrieve shipping prices in realtime, kinda like the UPS shipping module included in CS-Cart. The webservice documentation is in portuguese but I can provide it in english, and I can provide guidance on how to use this webservice. It can be invoked very easily via URL parameters. The shipping module will have to: - Allow me to set the shipping methods available in the store, as Correios offer multiple methods with different rates (Sedex, Sedex 10, Sedex 12, PAC, carta registrada) - Pass the size and weight of the product, and the origin and destination zip code, to the webservice so the rate can be accurately calculated. - Allow me to configure the origin zip code and some other parameters needed by the webservice. - Disable a specific method in case of errors. For instance: if I have both Sedex and Sedex 10 enabled, and the destination zipcode is not covered by Sedex 10, the webservice will return an error when calculating the rate for Sedex 10 and the shipping module must then prevent the user from selecting this option while allowing the others, or at least display some kind of warning about the error. - Display a warning if the webservice is down for some reason. If you have any questions about the project or Correios and its webservice, please let me know.