How do I make FotoMagico fade a track when "Interactive" is set for a transition?

I want to do a Fade Out of the audio track at the start of a presentation when the Continue at “Interactive” is selected for my transition.

I have a static introductory image on screen with an audio track playing while people are coming in and sitting down. The slide is set for “Continue: Interactive.” When it’s time to start the presentation, I want to click the Right Arrow button to go to the next slide – BUT – I want the audio track to fade out BEFORE or WHILE the next slide is shown (the audio track may or may not be looped). And, of course, there’s no specific time when the Right Arrow button is pressed, only when it’s convenient.

How can I get that audio Fade Out to occur (I’ve tried all kinds of things, maybe just not the right ones!)

Thanks,

Stan