wouldn't be easy
Though the reflected light from the sail could be used as a beacon so the pointing could be adjusted... like the way beacons are used in laser communication.
Another problem would be how to keep your transmitter in a stable orbit, since it will be propelling itself as it beams the energy out...
Look at the different scenarios at the end of the paper on pgs 33-34...
They give an idea of the time you need to stay on target...