Matching length of music to length of slide show

I have 183 slides, and 3 songs for my clients slideshow, can i make the 3 songs loop, and the slideshow keep going. Or make the length of the slideshow match the length of the music. i have tried the matching the music to the slideshow, and nothing changes. Any suggestions??

You can only match a number of slides to one audio track. So if you can join those tracks you can follow the common workflow:

The audio track always has to fit (visually) to the slides before the length of the slides will be modified.
Please see the screenshots below to make it clear.
First selecting slides and added the length of the audio track according to the 5 slides:

http://skitch.com/herrschubert/niumx/system

Second the duration of the 5 slides is modified, as I wanted:

http://skitch.com/herrschubert/nium4/untitled

To sum up, the audio track has to fit the number of slides in the timeline (visually). Then the track will play until its end, because the slides’ duration has been modified accordingly.