Help with transparency! *pics*

Ok here is the scoop folks!

Im new here and i need some help with flash 8

I am creating shape tweens with simple black and white drawings for an ebook that i am in charge of creating content for.

Here is an example of what i am working with:
(click thumbnail to enlarge)

Ok so the background color of the ebook is creamy/brown.

The background of my .swf files is WHITE.

How can i make the white transparent so i can have the black drawings nicely displayed on the brown background??

Any help is much appreciated!!!