I had the same problem, and since I don't have a pronto, I had to come up with a substitute. It isn't as neat obviously, but thus far, it's doing its job as part of a set of macros for a mx-900.

on = power, return
off = power, power

If projector is off, the "power" command turns the projector on, and the "return" does nothing. If projector is already on (for example, switching from dvd viewing to cable box viewing ), the first "power" will bring up the confirmation screen. The "return" will simply cancel the command. Again, it's not the prettiest solution, but it let's me switch activities without worrying about accidentally switching off the projector and waiting 5 minutes for it to come back on.

There may be one other drawback. I haven't tested this, but if the projector is off, running the "off" macro will probably turn the projector on.