Black and White masking principles (help please)

In typical programs like Photoshop, masks are determined by black or white and even grey. I am however having a few problems in Flash.

I have a motion effect that reveals some text. Now When the motion effect comes back I want it to hide the text, but even when applying black to a seperate mask it does not works it reveals the text. I must be doing something wrong somewhere and really need to figure this out.

Can anyone help me out here?

cheers

Trev

the colour of the mask doesn’t matter, could be white, black or blue, yellow …
Can you post your file to see the problem