Credit Cards

I am putting up a new shopping cart with NOPCommerce.  

During the checkout process how to I set the shopping cart so that a return visitor will see their existing Credit Cards?

I can't find the setting so that the return customer can see cards that were arleady entered.

The only two things that I can think of are:
1)  I am testing so my URL doesn't match the URL in the system.  I am using a subdomain
2)  My current subdomain isn't SSLed.

Thanks!