The iMIV and MII emulate a Melbus device. By default this is the 10 CD external changer. However, we do offer firmware that changes this to other channels. If you want to use the iMIV or MII and your head unit does not support these channels, you have to make a choice of what to keep.
For the new iMIV devices there is only 1 MELBUS connection. This means that unless you use a MELBUS splitter cable, the two can't exist on the MELBUS even if they use different emulation channels.