Alex, I was hoping this was a holiday miracle. Unfortunately, photostream (iCloud) is still not working even after updating to 6.0.2 and following your instructions above.
The same problems exist - photostream only loads about 340 photos of the 904 I have in the stream. iPhone, iPad and iPod all pick up 904. I even removed my pics from the photostream (again) and reloaded them from a backup. All other devices load up 904, Apple TV picks up 340.
Can you confirm that all of your photos are loaded on your Apple TV (and that you have more than 500 photos in your photostream). If you can truely see all of your photostream photos please again expain to us exactly how you did it step-by-step.
Anyone else get their photostream to work with Alex's suggestion?