no trick. at the top of the remote is a SET button, hold it until the light at the top blinks twice. the enter the code 10054. if that doesnt work for you, it might be a different code. call the call center for a listing or you can go online to comcast.com under the internet section to find a list of codes.
I have the instructions and code list and programmed my first TV/DTA without a problem. The second DTA and TV (Philips 32PFL3505D/F7) is a different story. I've been through the code bank multiple times (the connected XBOX turns on).