Shooping cart hamper

Hi there, I have an oscommerce shopping cart and have added a feature that allows people to have two duel carts running at the same time. The second cart is to the point where I can add products to it but I now need it to be able to checkout. When I try and checkout with it, it says my cart is empty. This isn't a big job, should only take a few hours and I need it done asap. There are more jobs like this in the pipeline though so if the winner is good, there will be more work going their way. Anyone interested? People saying it will take a week or they can't do it for a while need not apply.