I need for PayPal/ZenCart to send the user to a specific URL upon completion of transaction. I am using PayPal Website Payment Standard and do not see an option for it inside of ZenCart. PayPal has the option when I create buttons, but those buttons are not used on the site at all. Can anyone point me in the right direction?

If this cannot be done, is it possible to set up an auto responder through ZenCart to email the customer and tell them to visit a specific link? Would like it to be automatic, so I don't have to go in and email every single customer.