I'm trying to set up to sell MP3's on my website. I'm testing it and when I click "Add to Cart", the browser goes to a PayPal co-branded site, and shows the item# in the cart. Then what does the user do if they want to buy more than that just one MP3? I try to click the "back" key but the browser does not go back, but instead adds another Quantity to that same MP3 item#. The only button on the Paypal co-branded page is "Proceed to Checkout". Is there a way to have a "Continue Shopping" button and option?