How to export an automatically timed Keynote as a movie

I have made a presentation on a MacBook with background music and several individually recorded voiceovers imported from GarageBand. Each slide has a transition and builds, which uses delays so the whole thing works as a single runthrough "movie" when I play it.

If I export, I get several separate files (music and "video" both as separate .mov files, while the original mp3s do not show either.

I hope one of you Keynote gurus can help!

Daniel