Zen Cart

Hi, I have a project that needs to be done two things. 1. I have created a new interface for the product info view. Now in the back-end admin mode in product info, I want to make a drop down where I can choose between the new interface for the product or the old that is now. 2. The payment is already enabled and working. But I need to enable an extra 5% fee for using paypal on checkout. If you do a good job, you will be noticed when I post my other projects too.