This can be done, by adding a "virtual" or "pseudo" device to your activity. Add another device to your remote, preferably a type of device which is already in the activity (but a different brand!!!), except a TV, for example a receiver. Program for that device for the power down button your ir-code of your lcd-projector. Add this device too your activity and set the delay settings if necessary.

If you now switch off the activity the "pseudo" device takes care of the extra power down ir-code

Regards,

De Pampi