   Surface copy with alpha blending
  So I have a surface that I want to copy onto the backbuffer. The surface has alpha information that I'd like to blend with the backbuffer, but it seems that all of the surface copy functions don't allow alpha blending. Am I wrong?I was thinking I could draw directly to the top level of a texture instead, then use the sprite device to draw it using alpha, but is that necessary?What would people who know what they're doing recommend (to someone who doesn't).Thanks   