@wiskar - see this thread for some details on the diagnostics info:
http://forum.xbmc.org/showthread.php?tid=70743
That said, it only reports the core stream, so don't worry if it shows 1536kb/s - DTS core. Trust your amp.
I have a couple of builds, one based on AE (the first in my post above) and the other on Daniela's patch (second in post). The difference is pretty large - the AE branch improves mp3 & high-def FLAC output quality as well as providing the bitstreaming as Daniela's does.
Support thread for Windows AE branch:
http://forum.xbmc.org/showthread.php?tid=124600
Support thread for Daniela's patch:
http://forum.xbmc.org/showthread.php?tid=121877
Please post comments or support questions in the relevent one - they are both well-monitored for support. If you could, please let me know which one of the two you're using and your hardware & results in the relevent thread - would be very helpful as both as still very new!
If you're unsure which one you have, the AE branch will have the line "Audiophile mode" in Settings>System>Audio Output - Daniela's patch won't.
Cheers,
Damian