Sadly the wiring on the Japanese cars is *completely* different to anything else. The wiring on your unit looks like the wiring of the AGW in the boot of European cars plus some other stuff.
I think you will have to get the full COMAND loom and a European/Rest-of-the-world COMAND system and replace the wiring taking out as much of the old wiring - but all the old parts (such as phone systems, TV etc may also need changing). It is probably simplest to put the latest hard disk based system in.
Theres a chap in Sydney who has done this before, he is at
BenzModz
He'll certainly be able to do this for you
Richard