I Was Wondering If Anyone Had Any Experience With Opening A CD And Funding It With A Credit Card

I was wondering if anyone had any experience with opening a CD and funding it with a credit card?  North American Savings Bank accepts credit cards on line to fund a new CD.  So I called the customer service to see if they process it as a purchase or a cash advance.  The CSR said she thought it was processed as a purchase and suggested I call my card issuer.  Then she said let me check.  She came back and said it would be processed as a purchase.  If this is correct one could use a cash back card and really get a big bump on the effective interest rate.  However I am very skeptical that this is how they would process it.  Wouldn't they be paying merchant fees to accept the card as a purchase?  Any one with thoughts on this?