Hi. I bought a Mercedes C55AMG from 2005 in Germany. When I press and hold mute+serv+end call i get into engineering mod. But i cant open hidden menu. I tried *+#+<, 1+3+9, 1+3+< and it still doesnt work. Any idea. I just wanna MP3, not dvd in driveing. Also nav+5 worked.The system is command aps.