Hi,
Current tuners do not perform the function of the descrambler boxes that are metered to allow premium channels.
The way you use an AIW or Tuner card for digital or premium channel use is to simply plug the cable into your cable box, then run the cable box's outputs into the input block that connects to your AIW card.
From here, configure the ATI TV application to use the SVideo or Composite input (whichever method you connected your cable box to the input block) and use your cable box's remote control to flip channels.