What's available to improve the mirrors when towing a travel trailer? I'm afraid that my 2007 ML320CDI factory power mirrors won't be adequate but dealer can't suggest anything. My last tow vehicle was a dodge Ram truck with excellent flip out mirrors that still allowed power adjustment. The ML320 is advertised as great for towing but seems poorly designed in some ways eg brake control wiring and mirrors. Has anyone found mirror extensions that work well without detracting too much from the elegant looks of the vehicle?