Using Digirack 002 live on stage... do I need a submixer...?

[beelzebub2]

Hi there everyone,
I send my separate instrumental backing tracks out of Ableton Live through my digirack002 sep. outs, and I also have a live vocal mic, a guitar and a midi piano come out of there, which I play live during my set. My question is, since I could theoretically mix the levels of my sounds within Ableton, do I really need to buy/schlep a mackie (say a 1202) with me to gigs...? Couldn't the soundperson just take my separate tracks directly out of my digirack002 soundcard (btw it's NOT the mixboard one, it's the normal one)...?
To be more specific - i would like the soundperson to have my separate pre-recorded tracks as well as my live playing all separate so that he/she can mix it to sound really amazing. But I am not sure whether I need to channel my sep outs through a sub-mixer on stage before it goes into the foh board.
i am not fussy about my monitor sound. i would be happy to get it regurgitated from the foh board.
I looked in my digirack002 getting started guide that ships with the thang but it is very sparse with the info.
Thanks for your recommendations!