theres a couple things I may do to achieve this. Shoot the tv with a black screen and all the reflections should show up as 'clear' as they are going to be. Then overlay that black screen in AE with the add or screen composite mode. You can use your levels adjustments to tweak the reflection. Personally, depending on exactly what you are doing, I like to do my own 3d reflections and use them as an overlay.
That may not work depending on what you are doing.
Animation & Visual Effects
Los Angeles Ca
[Barend Onneweer]"If your camera is moving you may want to make sure you've got something to track. 4 small dots in the corners of the screen will do."
If you've got Mocha then you might not even need the tracking markers. If you do use markers make sure they're going to be simple to remove, especially if you're using a blend mode to keep the reflections.