Having checked the forums, this seems like an ongoing issue.

The Buy Now button in the shopping cart is repeated. Once at step 4, and in the email sent at the end of step 3.

Here's my suggestions:

1. Remove the buy now option at step 4, and allow the customer to payatreceipt of invoice email. (Not really a very usefulidea.)

2. Remove the buy now button from the auto generated email at step 3. (Best option)

If anyone has a better solution that doesn't involve recoding the html for the email at every upload I'd be pleased to hear it. Thanks