Until I watched Freetutorials' video on Bryce animation on March 28 and 29 - http://www.youtube.com/watch?v=8WYg1swDORI - I had been completely intimidated by the animation functions in Bryce - and reading user's manuals make my mind go completely blank... So, after watching that video carfully several times, I gave it a go, and here is the result. I looped it several times to make it fit the length of the music file.
Royalty-free music: "Guitar Musette" by Angelo Debarre, licensed from APM music - http://www.apmmusic.com