Channels 1-2 Grayed Out and Locked.

Any one know a work around for this? I have implemented a Summing Unit and I can't take full advantage of 8 Outputs that my sound card has. I could only use 6 outputs because again 1-2 are grayed out and forcing you to make those your main Stereo Output. I have made S/PDIF my main output. I have tried setting those outputs in other D.A.W.S and have been able to make whatever I desire as my main output/stereo out. Any help on this? Or is this a lost cause because the people at Logic choose not to listen. What is the reason for this? I can't comprehend as to why they would lock you in to that.

Best, Nevalu