If you do not want to use the soundtrack from video throughout, but would like to use it only at few selected sections of the video, you can use the Audio Boost feature. You can find this feature in the drop down menu for each clip and also in the magicMoments dialog box. Set the volume level for Video Sountrack to zero in Settings tab in Personalize. Then enable Audio Boost for those clips for which you want the video soundtack to be used. Hope this will help!
I'm having the same issue. Product: Reveal 8 Build: 2508(17654)
My home made movie contains multiple MPEG videos and pictures. I also added some music MP3s. I'm trying to find out is there a way to have the MP3s play only during the pictures and not during the MPEG videos I included. I couldn't find that portion you described in "magic moments" where I could exclude it from the MPEGs.