Hmm really strange. I just installed the drivers so I could test that new feature and it seems quite bugged, at least with the Z-5500.
1- If I keep the decoder's input at (Direct "Analog"), enabling DDL through the Auzentech pannel will activate for real but it won't seem to do any effect on the music I'm listening at. PS: The input in Vista is also set in analog (Speakers) as seen on this picture
HERE.
2- However if I keep DDL enabled and Vista in analog "speakers"
BUT put my decoder at (Optical "Digital"), it will show on my decoder under the Input, that I'm using the effect (Dolby Digital). The sound will sound as good, maybe a little better but every single volume trigger in windows will no more work, unless the mute checkbox. I will have to use the decoder to change the volume and like if thing weren't bad already... with these settings, the sounds is extremly loud, even when the speakers are set on the minimum so maybe the sound just seems better because its louder by default.
3- Now if on the picture above I select SPDIF, I'll have to choose (Optical) on my decoder to get any sound, which is normal. But all the special effects like CMSS-3D, Equalizer, Crystaliser... won't work and the Treble/Bass buttons will disapear in my Console Launcher. Keep in mind that this one is with DDL disabled... as if I enable it while being with SPDIF, any sound or song that I'll play will jam after 0.3 second.
So... WTF!?!?!?

. Not mad at you, don't worry but I'm sick of random bs like that, mostly for a product that I paid 170$ + Tax. I still can't believe a ridiculous thing like microphone output doesn't work. Oh, not to forget those f**** over Auzentech Support that even after a few weeks still haven't replyed my tickets.