I'm not sure I can help. Comcast has their own programmed codes that support many features from many manufacturers - but not necessarily all features from all manufacturers. Since they have the ability to program their remotes, and some remotes can "learn", you might want to call and see if they can help you program the button you're looking for. In some cases, they can do it over the phone. In some cases, it may require the expertise of a tech, and in some cases it will not be possible.
But I would recommend at least asking your cable provider.
I bought the HT-AS720 receiver for my LN52A650 and cannot find a Samsung Home Theater code that will work for the Aux button of the DVR remote with the RED "OK Select" button.Love the TV and the code for it works fine....Please Help!!!!Thanks