TRANSPARENT MASKS not transparent

[Vhihu]

Hi, I am trying to billboard objects and textures of people (jpgs) in my world. I have used Studio Max to make the masks, and it works fine-- the black on the mask turns transparent. However, once imported into Viz, you can see the surrounding black mask, and it is the image attached onto that black mask. How do I get rid of it? It's not that the masks are not completely black. Thanks!