AbleCommerce Shopping Cart Software

I'm trying to add a product to the basket via a URL and then go the the basket. I have tried to using http://yourstoreurl/AddToBasket.aspx?ProductId=1. I copied the code from http://wiki.ablecommerce.com/index.php/Adding_products_to_the_cart_from_external_entity. I get an item cannot be found error....

I have several digital products. I want to load a list of serial keys for each product. I don't see a way to load serial keys in the Digital Goods or Product setup. What am I missing?

I'm changing our cart over to able commerce. I want a URL to put a product in the basket with a discount code. This will track which email a sale came from as well automatically reduce the price to the correct level. How do I do this?