garageband / presonus fp10 live recording quality

I recently recorded a guitar using garageband from iLife 08 via a presonus fp10 firwire interface. I plugged the guitar directly into the intrument level input, so there was no microphone involved. I found that once I was recording, I could no longer adjust the recording level. (geez, really?) I also found that I had to set the recording level to automatic to get a decent recording. hmmmm. If you are recording a song that is really loud at the beginning, I susepect it would not react very fast and clip.

Anyone have any good advice for recording live music with up to 8 channels and a way to be able to adjust recoring levels during recording?

thanks for any info.