Even though I owned a W210 diesel, I am not sue about the key systems on the newer diesels. A diesel is a tougher remote start install becase it has no ignition system. It's not that tough to get it going, but turning a diesel engine off is not as simple as a gasoline engine. MB "ignition" switches have a vacuum system that kills the engine. We had to rig up a vacuum switch with the remote start system. I understand that that there are more diesel specific systems available now (there used to be, but not in the brands I liked) and you should be able to find one, but if not, make sure your shop knows how to install in an MB diesel.
If you're curious about remote start installs (NOT brands, because they are lots out there, but on the INSTALL part only, here's a thread I wrote years ago...)
http://www.peachparts.com/shopforum/showthread.php?p=61351&highlight=remote+start#post61351