You will need a special Audio Aux Link cable. See: http://forum.beoworld.org/forums/thread/101338.aspx
BM7000                  BS9000
 Pin 2----------------------Pin 2
 Pin 1----------------------Pin 3
 Pin 4----------------------Pin 5
 Pin 3----------------------Pin 1
 Pin 5----------------------Pin 4
Thanks to Søren... 
Main difference is you don`t have a BS 7000 but a BC 9300.
You can listen to whatever is activated on the BC 9300 by pressing A.AUX on the BS 9000.
Hope this helps.
Stefan