As far as we know, you cannot use our services with a Yahoo! store because of the way they have choosen to set up their payment processing gateway. We are not compatible with their gateway services at this point in time.

You may be able to find a 3rd Party Shopping Cart that can meet your needs.
http://www.2checkout.com/community/blog/category/knowledge-base/tech-support/3rd-party-carts/recommended-carts/