Help with animation problem

[biographics]

I have Powerpoint 2008 for Mac. I have a slide with the 5 lobes of a lung that have animations applied so that on click each of the lobes on enter fades in one at a time until the whole lung is there. In slideshow when you hit back it goes back only to the last animation action not to the beginning of the slide itself. My client insists it should go back to the beginning of the slide. Am I doing something wrong. In my slide you have to click back 4 times ( through each animation) to go back to the beginning of the slide. Help