Thanks gonk.
I'm actually in Westchester now, north of NYC, and we have Cablevision, not Time Warner.

I am not sure which HD box Cablevision is using (but they too have disabled the HDTV out: "At this time, the television industry has not determined a standard for either the HD signal transmission or the connection of HD equipment to other home entertainment equipment. Because of these unresolved issues, Cablevision's digital box currently is not capable of passing an HDTV signal.") I didn't realize that.

I do know that they support cablecard, as a friend of mine is using it. Unfortunately I haven't been over to his place to use it yet, so I'm not sure if it's A/D converting the analog audio, or what HDTV format it is sending to his display. I'll let you know when I go test it out.