UV Mapping + Alpha?

I have used alpha mapping with normal image mapping through the texture channels. However, I have not figured out how to get it to work when a mesh is UV mapped. On the left, you can see a model with normal image mapped texture channel. On the right, I am trying to UV map the alpha map to a cylinder.

I do not know how to tell it to make the white parts see through. Can I even do this? Is there a calcAlpha button when UV mapping?



I mapped the same image onto the mesh again in the texture channel and used the UV coords to map it properly and then set up the tranp as I usually do!