I just encountered the same problem. I bought a new Onkyo receiver / and new IPOD dock a month ago. I had a two year old 60G Video IPOD which worked with it, but since I was running out of space - I made the mistake of upgrading to a new 160G Classic. If I want to use it with my TV, I guess I'll need to buy even more cables or docks from Apple. I read that no dock (not even Apple's) lets you use all the remote control features so it will be a manually controlled wiring kludge.
I've contacted Onkyo, but I note in their manual that the Classic is not covered, so I'm sure they won't be of much help.