audio video sync

Just starting using Garageband and FCP X to make music videos with my kids. I am trying to sync a video of my son playing drums with audio from GB. I shot the video with the webcam on my macbook pro and recorded the audio using 2 mics thru an audio interface into GB. I exported the audio into iTunes as an AAC file and imported it into FCP. I didn't start the audio and video at the same time and I didn't think I needed to . The video has some footage at the beginning before he starts playing and the audio starts on beat 1. When I attempt to sync the clips, FCP puts the GB audio at the very start of the video instead of syncing it where he starts playing. Any help is appreciated, thanks.

If you recorded audio with the web cam as well, then FCPX should sync everything with a click.

-- E