I think I can deal with the problem in a different manner. For those interested:

The pronto (9800) controls my theater by sending commands to a PC that directly controls the theater. A command is a message consisting of two integers. The first is a component ID and the second a function ID just like most IR remotes.

To the left of the 133" main screen, there is a 24" monitor that has system status. I am getting bothered by looking at it since it is always on and it is quite bright. What I plan to do is blank the monitor's screen N seconds (N to be determined but around 15-30 seconds) after the PC receives any command from the Pronto. Any command received will un-blank the screen. That will cut down on the ambient light and eliminate the distraction. I have to see if I can turn off the backlight on the monitor without turning the monitor off, perhaps 'sleep' will work.