If I have chosen a theme for my slideshow in iphoto can I override the music that goes with the theme or am I stuck with it?

I'm short on time. I've chosen the scrapbook theme for my slideshow and am very happy with the way it turned out. However I don't want to use the music that comes along with the scrapbook theme (you've got a friend in me). I'd like to replace that with a song from my itunes library. Is that possible? Thanks.