I am not an expert nor an experienced user in this area, but hopefully my questions will bump this for you.
Link Room
Are you saying that you star N.MUSIC in the link room ?
Is this an audio only link room, or does it have a BV ?
Main Room
After you started N.MUSIC in the link room what do you find playing in the main room ? nothing ? something: N.MUSIC ?
Then you press [PC] right ?
And you can see the BM5 video signal ... do you also get the N.MUSIC audio ?
What has happened in the link room ? is it still getting its N.MUSIC ?
Other "Symptoms"
Does anything happen to the BS 9000 when you press [MENU] for the first time ?
Does the BV menu come up with the immediate pressing of [MENU] ?
Thoughts .....
On my BV8, the [MENU] key behaves differently depending upon the source I am "talking" to.
In [PC] mode it depends very much on the application behind the screen.
Sometimes I have to press double [MENU] to get the menu for the BV8.
So I suspect your first [MENU] command is not being passed through to the [PC] interface.
I suspect this is going to come down to tricky options settings, to get the [MENU] command to be sent over the MasterLink.
Better contacts :)
Philippe probably does not regularly monitor this forum, however I suspect you need his level of integration expertise ... might be worth PMing him
Philippe's Profile Page
First B&O (1976) was a Beogram 1500 ... latest (2011) change has been to couple the BL11 with the BL6Ks *sounds superb*