Google Checkout API integration for e-commerce project

Ladies and Gentleman, we do need "Google Checkout" integrated into an auction site. It should work that way: after costumer has won his auction on our site: 1. If seller choosed "google checkout" as one of his payment possibilities 2. buyer will be let to a site with the google checkout buttom 3. When he clicked the buttom he will leave the auction site and go to google checkout. All relevant data from the auction will be forwarded to google checkout. 4. then the buyer pays on the google checkout site directly to the seller. Not the middle way to the auction site. 5. Buyer clicks on buttom and leaves "google checkout" and comes back to the "auction" site Payment is 100% after finishing job. We´ve made bad experiences. You need to programm the API working with j2ee java auction site on MySql. best regards Daniel Schmidt