iBook 500 and Digital Performer, Info regarding mulitple outputs from iBook Options

Is anyone using an iBook and Digital Performer? This iBook has 2 USB ports and the mini-jack audio out. What I'm trying to accomplish is 2 seperate outputs using an iMac and the audio output jack. How do I tell DP to recognize both outs?

OR>...is there a way for iTunes to be exported on 2 outputs (iMic USB port and the audio output)?

I am a trying to get it so I can run 1 output to my stage mix and the other output to the monitor board for the rest of the band. That way i can control the level of the loop in my ear mix without having to rely on someone changing it for me.