Can no longer purchase apps via my phone bill after moving to a GS2

Hi guys.

Since I upgraded from my old HTC Desire, to my new GS2, I no longer have the option to pay for apps in the market through my phone bill. My Google account hasn't changed, and I can't see why this option is missing in the payment type drop down list.

Anyone got any ideas off how to get this option back?

Thanks in advance.

Andy