[LAU] Lexicon Omega USB interface and low microphone level

I have a Lexicon Omega USB audio interface, which works mostly fine on my Debian testing system with kernel 2.6.26-2-amd64. The device has an onboard mixer, and no mixer interface appears to alsamixer. This is fine, but I can't seem to turn the microphone levels up high enough. In ardour for instance, if I crank the microphone level all the way up and yell into the mic, I can just get the signal up to -3db. That's not enough to record anything quieter though. When doing this, the peak indicator lights up on the device, so it seems to be working properly. I've been using linux audio and ardour for quite a while using other sound interfaces with software controlled mixers and it has worked fine. Is there something I'm missing on how to turn the levels up? Thanks! Joseph Sheedy Seattle, WA