There is a way !
If like me you dont narrate but now and again lower the soundtrack of the actual video clip and then have a separate
possibly music sound track underneath, I have found the way to make Audio Ducking respond not just to voice narration but also to clip sound track.
The key to it all is that Audio Ducking doesnt so much response to the volume of the narration rather to the presence of it.
This you can use. Say you have a video clip where you, in places, want the sound to 'go down' a thus the music to 'come up'.
You can make audio ducking respond to this as follows:
at the point where you have lowered the volume of the video clip completely, insert a clip split. Where you want the clip sound to come back insert another clip split. Now MUTE the bit inbetween the splits.
If you now add a music track and apply Audio Ducking you will find that the music comes up where the video clip is muted and goes down where it isnt.
This is a partial solution of course, If you just want to reduce the video sound a bit rather than mute completely, then this wont work. It only works where you mute a clip. but its not a bad half way. As adding music or additional sound is the last thing I usually do, it will still save time and a lot of messing about. But Cyberlink please sort this out. Audio ducking needs to be more sophisticated and react to volume also.