"The DataConnect Pass plan is a flexible and convenient way for customers (including non-AT&T customers) to buy prepaid mobile broadband data service.
Your DataConnect Pass plan will:
Be billed to debit/credit card
Be active for 30 days or until depleted, whichever occurs first
Automatically renew every 30 days (Auto-renew option can be canceled at any time)
Not require a service commitment or activation fee"
I see no mention of prepaid cards. Could just be an oversight on their part though. I honestly dont know.