This worked on my CL600. There was an IPod cable in the glove box that this gizmo plugs into. Worked great! All I had to do was add "Aux" to my selection menu on the radio and was able to stream Pandora from my phone. I just leave it in the car all the time. It will connect the second I get in the car.
Since it appears you have the cable already, this should work for you.