If you want to automatically return the user to the page in the return element you need to have auto return enabled, do you have this enabled?
If you do then PayPal will automatically return the user to the URL that you have specified in the return. When I do a view source on your confirm page it looks like you have the return element setup correctly so you just need to make sure that you enable this in your PayPal profile.
All that the return does is send the user to that URL, it does not pass anything along.