Slideshow Music tapering

i created a slideshow of my ancestors and chose the "show titles and comments" so my relatives would know who they were looking at. i added music. PROBLEM: music stops abruptly at end of DVD--how do I taper the music like I am able to do in IMovie?

I tried importing the entire thing into Imovie so I could control the music, but then I couldn't figure out how to keep the titles and comments for each photo.

Any suggestions greatly appreciated