Win-7 audio mixer and application configuration

[Nomen]

On this particular win-7 laptop I have 4 audio-out devices according to the tray sound mixer application.  In the mixer, I see a window with a drop-down where I select the device, and in the right-pane are the applications currently running (browsers, maybe VLC if it's running, etc).  But I only see these apps for one of the audio devices.  I've just paired a bluetooth amp - but how can I select a particular app (say, VLC) to output to it?