I am not an iPod user so my knowledge of this subject is limited. However, I know that many of you are as passionate about your iPhone as you are about your Mercedes-Benz.
The new MultiMedia Interface cable in the 2009 vehicles has been a wonderful upgrade for interfacing with iPods and iPhones. It is very easy to access folders and artists right from the main command screen. A problem with the system has been that when you plug in your 3G iPhone it gives a message that it is incompatible and unable to charge. According the to Apple website this error will probably also happen with 4th generation iPod Nano and 2nd generation iPod Touch devices.
From – Benzworld.org Forum Post