I have an easier way, I think.
Just load the sprite, make sure the viewmode is "always facing camera," and then do this: Position the sprite at your camera position, rotate the sprite just as your camera, and MoveEntity sprite,0,0,1. This will put it in front of your camera (make sure this is done each loop). Then, it's just the matter of setting up the variable alpha#, add something like .1 or .01 to it when it's fading in and subtract .1 or .01 while it's fading out. Just do EntityAlpha sprite,alpha# and bingo! Instant HUD (or whatever the sprite is).
Just load the sprite, make sure the viewmode is "always facing camera," and then do this: Position the sprite at your camera position, rotate the sprite just as your camera, and MoveEntity sprite,0,0,1. This will put it in front of your camera (make sure this is done each loop). Then, it's just the matter of setting up the variable alpha#, add something like .1 or .01 to it when it's fading in and subtract .1 or .01 while it's fading out. Just do EntityAlpha sprite,alpha# and bingo! Instant HUD (or whatever the sprite is).