try it on my E46 and it work. "Business version"
Procedure is as follow:-
1. Off the radio when the ignition is turn to "accesories" position.
2. Turn on the radio by pressing the "ON" key. Keep holding the "M" key within 10 second after the radio is turn on until you see the LED display on the radio display the serial number.
3. After the serial number is display, press hte "+" key until you see the area. Your display should display "Japan".
4. Press "1" for USA, "2" for Europe, "3" for Japan or "4" for "Ocenic".
5. To set the key, I think you just the "On" button again or something like that..
Thank for the links by other forummer.. (ron and shaifulo)
BTW, when you set the clock on the display dashboard, the time on the radio will also follow the time shown on the dashboard.