Return xml from a method inside a class

 I have a class file called ShoppingCartClass.cs. Inside ShoppingCartClass I have a method called CanadaPostShipping.
CanadaPostShipping get passed a lot of variables and then builds an xml, sends it to CanadaPost url and gets back an xml file with the shipping rates.
I would like to pass the xml back to my webpage so in my web page I can check that it has status ok and then extract the information I need.
My testing calling routine looks like this:
ShoppingCartClass scc = new ShoppingCartClass(); scc.CanadaPostShipping(my_cart_total, my_item_name, my_quantity, my_weight, my_height, my_length, my_width,my_add_city, my_add_prov, my_add_country,my_add_postal);
 
 
The start of my CanadaPostShipping routine looks like this
//------------------------------------------------------------------------------------------------------- ...