thanks for asking.

For the time being, I don't know of an off-the-shelf way to switch 
between speakers.

You can, however, open System Preferences directly in a specific pane 
by adding f.ex.

/System/Library/PreferencePanes/Sound.prefPane

to Remote Buddy's menu via drag and drop from the Finder, then later 
choose that item from the menu.

Best regards, 
Felix Schwarz