Hi, I'm a dealer guy, I may have some advice that will help. I don't believe the ML is similar to the C-class as far as the antenna. I believe your car still has a "regular" power antenna, the ML is a glass integrated antenna, the rear hatch glass. Check out behind the left trunk trim, the splitter is there, mounted to the antenna assembly. For power, you should be able to use the one for the factory pre-wired CD, this would avoid running a seperate wire. It would be good to get the wiring schematic for the factory radio, and CD changer. The wire for the CD changer is behind the right trunk trim. It is a 3 wire. One is power to run the CD changer (provided by the radio, ground (also provided by the radio) and a "wake-up" line from the radio, to get the factory CD changer to get on the D2B (fiber optic) ring.
Gilly