My iPhone 4s was having the same issue with the video not working. After I upgraded to iOS 6, I lost all usage of my phone. No ipod, no pandora, and now I get the "charging is not supported with this accessory" message when I plug it in. It also wont work with an iPhone 3gs running iOS 6. Major bummer, as I used pandora all of the time......

 

I have a avic f900-bt with firmware 3.something and the parking brake wiring mod.

When you set AV1 to video mode, you can play everything that way, right? Just no ipod connection anymore?

I had a hunch and confirmed it yesterday. Maybe this is obvious, but you need to have music on your iphone for it to show up as the ipod icon. I had a fresh install of iOS 6.0 and iOS 4.1 with no music and I could not get the icon to display. I had to use AV1 set to video instead which was annoying. To me, it should detect it as the iPod either way. Kind of dumb in my opinion, but most people probably have music on their phone. Mystery solved. I'm actually loving 4.1 on my 3GS again. It's quick! Love how the new iOSs make you feel like it's time to upgrade your phone. Kinda convenient for apple...

Anyway, hopefully that helps someone out there.

Thanks