Well it's not so working the way I thought it would so what am I doing wrong?

To explain more clearly what I'm looking for is for the words in the image below "Alpha Please" to be mapped on my object, but the checker pattern be ignored due to the alpha.

Do I have to do something with the color balance? When I try it affects the whole bitmap, not just the alpha'd area. Should I be using Alpha Gain or Alpha Offset ? I've searched the docs and can't find any explaination of what these do. I've tried changing their values but I have seen no effect.

p.s. sorry the image quality is so poor, but 15K was hard to get to.