I think I switched the control over to the iPhone by pushing the function button while the source was set to USB, then turning the knob until it said Control Mode and pushing in on the knob. If that doesn't work, I'll check tomorrow and let you know.
Right now I don't have any type of holder for it, just have it sitting in a little compartment next to me . I plan on buying one soon though. The only two types that I've seen are the ones that fit into the cigarette lighter and the ones that clip onto air vent. I don't know if I like the idea of having my air vent blocked though since it's pretty hot and I can use all the air I can get. I'm going to start searching for a good one. Let me know if you come across anything. It was after reading one of your posts that I decided to pull the trigger on FH-8000BT, so maybe you can help me out again.