I've just bought the official Samsung car holder / dock.
It's well made and a perfect fit for the phone (without case) but I'm having problems connecting to my car stereo.
After a bit off fiddling with settings (turning on USB debugging) I can connect my GalaxyS2 directly to my Pioneer DEH-2300UB headunit with the USB cable.
GalaxyS2 then detects that it's connected by USB. Pulling down the notification bar and clicking the USB icon turns it on. It is then detected by the headunit like it would any USB mass storage device and plays MP3 files.
But if I connect the car holder to the headunit with the USB cable, then clip my GalaxyS2 into the car holder, the phone goes into car dock mode.
I can get out of car dock mode by pulling down the notifications bar and turning it off but I can't get the the phone into USB mass storage mode.
Any idea how I can get my GalaxyS2 to detect the USB connection and not the car dock?