You can run the front speakers through 1 and 2, the back two through 3 and 4, and the center and sub through 5 and 6. For the center channel, create sends for the four main channels and bus them to the center channel and the sub channel, create a low pass EQ for the sub to filter out everything above 120 Hz.
Thanks... however, my surround needs are more complex than that, requiring surround panning and multi-channel effects. I am busing out audio from Live to Logic via Soundflower, using Logic's surround panners and effects. Works great.