Did you actually read any of what you quoted or the reply? My suggestion had nothing to do with dual audio outputs, as the 2nd quote pointed out correctly.
Anyway just an update to this problem for the others that wanted the ability to switch audio outputs without extra windows steps, apparently my request is really implemented in XBMC already. I'm using WASABI Nvidia HDMI out as my main option, and by switching to WASABI SPDIF output, I don't need to change any Windows audio settings, as it dynamically outputs to the correct output just via XBMC.
Unfortunately changing Audio settings cannot be done via python script directly so instead I made a 2nd XBMC profile and set one to HDMI and the other to SPDIF. (I also made the SPDIF profile auto choose 24hz), I then made a button on my Harmony One to switch profiles and turn my AVR on.
So now I just hit "Master Mode" on my Harmony which gives 2.0 channel HDMI sound output to the TV (which it does by default).
Hitting "Movie Mode" on the Harmony One changes to SPDIF 5.1 sound checks the DTS, DD decoder mode options and also does Auto Refresh on the video side.
Then i just flick back to "Master" when I want sound thru the TV again. Sweet!
Hope it helps somebody, I can't see why it wouldn't work under Linux as well.