Yes Marco, this is related to this :
Note though, that that will select your DAC for general computer sounds as well. Never mind those for now.
... which you apparently already have arranged for.
Please be careful here;
In the past you may have put a lot of effort to get it that far (implying KMixer to get out of the way), and if you don't like XXHighEnd you might want to do it again.
Since I hardly care about this (I don't need it because of XP bitperfect RME (Fireface) drivers or Vista where all just doesn't apply), I am a bad advisor here.
You might want to go to Bert's site to re-find what you did before (and undo it by that means), or otherwise I sure hope others can help you out.
Whatever you do, try to write it down, so you can reverse it when you think it is needed.
Btw, of course in the end you would just
want to have it like you have it now (see my quote), but then including the device being the primary device.
Also note that the fact that it in the end is greyed out is not a problem, as long as you get it there (at first place hence Primary Device).
As soon as I see something to help out a bit, I'll jump in !
Peter