Hi...

You will just need to disconnect the CD Changer temporarily to access the iBus. You will find there are two cables plugged into the CD Changer.
There is a 6-Pin and a 3-Pin (Ibus Cable).
Unplug both when doing it, then when your done you can happily plug them back into your changer.
Works a treat. You can also play with different options with your Navigation.

Regards
Rod.