The same concept is used by Azgalor The Pit Lord, one of DotA Heroes, his ability is Firestorm (old version)
He doesn't need to maintain the channeling for the Firestorm duration, instead a dummy is created at its position (or the target point) and the dummy who channels the Firestorm instead of Pit Lord
So, he is just faking the ability and the unit that do all the work is the dummy.