I still cant get jack working properly.
Here´s how i set up with VAC now:
In VDJ my soundcard is set to Mono-Separated and uses Line1 Virtual Audio Cable.
Output is set to external mixer - Left deck=Left Chan/Right Deck= Right Chan.
With this setting i get a mono channel for deck and b in ableton. But my BCD3000 is only able to be running in wdm mode this way. In wdm mode the same signal is routed to the output and the headphone cue, basically turning a 4 channel soundcard into a 2 channel soundcard.
Damn it, i cant cue this way!
This is where Jack comes into the picture. I got it to a point where i routed the 2 stereo-outputs from the bcd (left and right deck) into Ableton. But i was not able to route it back into the bcd.
This is what it looked like:
BCD outputs 1-4 into live´s in 1-4.
live´s outputs 1-4 into system 1-4.
But (!), strangely i was shown 1-8 outputs for my system. This must be my inbuild soundcard i guess (desktop pc soundcard with 5.1 or 7.1, idk). I then changed the systems main soundcard in hardware settings ( XP) to use the BCD instead of my inbuild soundcard… (btw, i only had sound coming to the speakers when i used 1-4. 5-8 had no output routed, either to the bcd nor the pc´s card. So i dont think jack is howing all possible outputs connected to my pc. instead it is showing only the outputs of the device that is set to be used as window´s soundcard)
I than was shown only 2 system outputs instead of 8. Must be the effin´wdm mode again. The bcd only allows for 1+2 and 3+4 outputs in its native asio mode. Not when using Jack, VAC or asio4all.
Now i am wondering if there is a way to use both my bcd´s soundcard and my inbuild one simultaniously, the bcd for main out and the inbuild one for cueing? Is it possible to let jack see the 2 cards as my system soundcard? This would be superduper, as this is my only problem right now. not beeing able to cue properly…
and on a similar note. i may have got something twisted in my setup with jack and my inbuild soundcard. I have a external mixer hooked up going into the speakers, beeing fed on one side by the bcd main out and the other side from the pc-out. With the crossfader all the way to the pc-side, left deck in ableton was sounding great, but the right deck had a massive buzz, like a feedback loop from deck a. Could this be? I am confused, as the pc-input was not used in ableton.
I had the mixer set up because i wanted to keep my music output and my pc output seperated, therefor no ugly msn sounds when spinning and chatting 
zac, thx for your link. I think its really helpfull, and next time i get to try it out, i will.
Bento, did you run jack on winXP? if so, what where your settings like? In jack itself as also in asio4all?
ps. i have a little usb soundcard from my imix reload laying around here and i´m wondering if this unit will run lower latency than my pc´s card regarding jack´s setup.
thx guys 
