the other day, i was doing (or trying to do) a sound fader.
I had the sound working already, working as property inside model, had to do it like that 'cause the sound had to be controlled by a sound toggle in a couple of places and didn't want to have two sound instances, and also want to have the controlled binded to the sound instance state (off, on)...anyways maybe that would be a tale for another time.

my first idea was to use a property, animate its value (AnimateProperty), and then updating the sound volume when the tween gets updated, pretty good on paper.