Alpha channels and write-on text

I have a write-on behaviour on a shape (with Image Mask applied) that reveals some text underneath that is actually a TIFF file with transparency. I want to know if I could actually use the ALPHA channel within the TIFF file to convert to either the shape that draws the text, or as the image mas. This will then give me an accurate outline of the script font.
My other issue is that I want the shadow to draw at the same time. The normal shadow is switched on but it is not visible in the animation. With Drop Shadow turned on, the rough outline of the shape reveals it but it is the shadow from the text, not the shadow from the light in the scene.

Thanks.