[AS3] Alpha mask?

1

Hi

I can’t figure out how make an an mc **alpha **mask to work in AS3. Here is
my try:

mc1 = new green();
mc2 = new blue();

mc2.blendMode = BlendMode.ALPHA;

addChild(mc1);
addChild(mc2);
mc2.cacheAsBitmap = true;
mc1.mask = mc2;

Anyone?

/brian