Break Apart Transparency Problem - Flash

[COLOR=#000000][FONT=Times New Roman][LEFT][COLOR=#333333][FONT=Arial]Hey guys!
I need help.
I imported a .ai file onto the stage and i wanted to make it a mask.
So i break it apart, but when i do that, i loose the transparency; the result is that my mask is now a big rectangle.
How can i keep the transparency for my mask?
Thanks
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