DUB DISCUSSION BOARD

I bought the Edirol FA66 Firewire interface
It has 4 jack outputs,
but when i plug into my Mixing Desk they each take up 2 channels,
so its only letting me play out 2 tracks at a time,
is there a way to get around this?
or do i need a different interface.

Thankyou! I am thinking of the following setup. Playing my guitar, MIDI keyboard through the Maudio 1010LT into my Macbook. Then sending this out to my mixer with reverb and delay aux hook ups. Ive seen pictures of the 1010LT but dont understand how this hooks up to my Macbook/ guitar? Any help? :D

Can i put a midi keyboard through the 1010LT MAudio PCI
And use the VSTs in cubase so it can be my keyboard and drums..?