I'm not sure what you would want to do this. The projector itself is a 720p projector. The actual DLP chip inside of it is 1280x720. You can't change that, and I wouldn't suggest doing it.
With a scaler you may be able to feed the projector 1080p - but then the projector would be forced to drop that back down to 1280x720.
Why?
Say it again: The projector only has a 1280x720 DLP chip inside of it.