Recording Narration for Keynote?

According to the KN User Manual, each KN slide can be narrated with an audio file so that the audio plays for that one slide only and stops when that slide leaves the screen. But the user manual does not say how to record this narration. Is there a way to record narration, one slide at a time, using a UBS mic, directly into Keynote as I'm building the presentation?

Right now.... my procedure is to export the KN, no audio, presentation as a QT movie: DV NTSC Low Quality compression, at 8fps. (Any other frame rate and the QT movie is not the same length as the Keynote Presentation. I made a one minute test of this and only changed the frame rate settings. 8fps gave me a 1:00 QT movie, but 29.97fps gave me :58. Over time, this two second loss can really add up!)

I then imported that low video quality QT into Final Cut and used the voice over tool and a USB mic to record narration as each slide rolled by. I then exported just the audio track, since the video was just there as a low quality guide, and I then put that audio track in iTunes.

I then went back to the original high quality Keynote presentation and dropped the narration track into the first slide with the media option. For at least the one minute test, everything was in sync through ten different slides.

Is there an easier way for me to get narration into a Keynote presentation?

Thanks, Steve