Getting an mp3 file to run throughout a Keynote presentation.

[somewhatvaguely]

For a school project, I have to record a podcast, with pictures for emphasis. I'd like to record something on GarageBand(for effects, and easier use) rather than use the narration tool in Keynote. I have Keynote 09. I read on the internet that it's possible to put an mp3 file in there, but it stops on each slide. So what can I do? If it comes down to it, I guess I can play my mp3 file as a narration, but I don't really want to do that. Help?

 

[illegalprelude]

that is a limitation of Keynote. Songs play on a perslide and thats it. They dont transfer from one to another unfortunately