if the TV says it...
... does not support HDCP, I would not buy the ATV2. My nine year old Sony KV36XBR800 CRT did support HDCP and 720P, so I gave it a shot. It has a DVI and not an HDMI port, so I bought an HDMI Switch and now the ATV2 and my TV are playing nice with 720P.
I wish I had better news for you...