routing Traktor using Digi 002?

[tritonkorg]

I'm in the process of learning Traktor DJ Studio and came across this problem and i hoped some one could probably solve this mystery for me.
When mixing 2 tracks, you need to cue or pre-listen to a track befoe you cross fade it into the main mix, therefore this software requires 2 stereo outputs. Now i'm using my didi 002 as my sound card and two of my monitors that are hooked up to it. Traktor has a audio set up section that you can do the routing for the master audio, and headphone ..etc......Now, i understand as the main mix is playing, you would want to use a headphone to pre-listen to the second song that you want to cross fade into. Is there any way, that i could do this with digi 002?....to be more specific, is there any way to hear the main mix through the monitors, but hear something else through the headphone at the same time?
The manual says, assign the master channel to output 1 and 2, ...and headphone channels to output 3 and 4 in the audio set up of Traktor, but i don't understand how this corresponds with Digi oo2?

Please advise if possible....thanks