Reply to HELP hooking up numark mixtrack and numark DJ I/O soundcard.

I can't figure out how to use the headphone output on the numark DJ I/O soundcard. I'm running both my Mixtrack controller and soundcard through the usb drives in my macbook. Is there a way I can send the cue to my headphones through my dj I/O soundcard, but send the master track to my computer speaker? Ive tried to use the output 1 on my dj i/o to connect via rca's to my reciever on my home theatre, and it works, but I hear the same track in my headphones. Any help would be great. Im kinda new to all this. Thanks