HI, on audio-10 when only 12 digits are displayed you can clear 4 digits using the CLR button to see the last 4 digits.
I dont know if the Audio-30-APS has a CLR button.
You can always do the pairing in another Mercedes (pop into dealer and ask)
One thing to note is that once the pairing is complete, many phones go into "remote sim mode" and are effectively "disabled" thus you can't use them and have to use the keypad on the stereo. I dont think the Audio-30-APS has a keypad ...
The Viseeo MB-2 will also work in a D2B car (like yours) ,
Comand Online Ltd :: Phone Cradles & Adapters :: ViseeO MB-2 (formerly MBU2000) UHI Bluetooth for Mercedes Benz
Richard