Mercedes-Benz has received a number of reports stating our clients in model year 2006-2009 vehicles with either the iPod interface or Media interface system are having charging problems with new 3g iPhones, 2nd generation iPod Touch and new 4th generation iPods. This is not a Mercedes-Benz defect, but a change in the Apple circuit design. When Apple produced their new products they changed the charging pin or charging circuit. The Apple products do function correctly but it does not charge the product.
I will keep you updated with any news from Mercedes-Benz.