Logic Pro 8 M-audio firewire solo


Hello, I recently purchased and enabled a M-audio firewire solo for Logic 8 (G5 2.66 mghz dual ppc)
The input and out put channel selections show 1-4 each. Although only 1 and 2 work in, and out. The solo is a 2 channel device. Is Logic displaying 3 and 4 for the internal audio? I bought this expecting to get 4 audio inputs. Any help here is appreciated.