I've never hear anywahere that DB natviely can read or display flash files...
However, if you want to use flash to develop your cutscenes then that is not too difficult.
x1b's suggestion is just what you would have to do. Export the flash movie to frames. You could do it in layers as well.
I didn't use DBPro with this method, but when I made a Bomberman clone "Bomber Joe" I used flash to animate my characters and to build my gui and other animated parts.
It helps to make a lot of graphics using vector graphics because you can export the rater images in different resolutions and not have to start from scratch.
A good plugin idea would be to render SVG tag. I would attempt it if I had time. I think it would be a very powerful addition to a game engine. Using vector graphics wih in the engine and having the interaction like the pick and mouseover internal would be really cool.
Oh I'm of to my class

!
Cheers
IDIC (Infinite Diversity Infinite Combinations)