Using shape as mask

hey guys,

Just having an issue with using a shape as a mask. I basically draw onto an empty shape object i create using its graphics property. This works as i can see it once i use addChild however a problem arises when i draw say 2 (or more) separate rectangles and set the shape as a mask on a movieclip. The area (the seperate rectangles) defined to be the mask along with the area inbetween the seperate rectangles becomes the mask.

beginFill(0x0000ff, 1.0);
drawRect(10, 10,50, 10);
drawRect(10, 30,50, 10);

so using the above code as an example, the rectangles drawn are independant, i.e they dont overlap. However when i set mc.mask, the area inbetween the rectangles also become part of the mask, which is not what i want.

Any help would be greatly appreciated on getting round this…Thanks!