Radio's properly installed now, got the antennae last week or so. Tucked it away under the passenger carpet, probably not the best location but as long as it can get some signal I'm happy, not gonna use the navigation on the unit anyway.
Inserted my new navi discs to update the system, which worked fine. Unfortunately the car's in an old garage that was built as a bomb shelter during the cold war, so the concrete roof is not letting neither radiation nor GPS-signals through. So that will be tested later.
Finally, didn't recieve a manual for this unit since it was sold as a replacement unit. Gonna order a manual from Mercedes, but in the meantime, how the hell do I access the settings menu? Heard something about second and seventh key, but no reaction on my unit. Anybody?