I don't think this would work. He would have to drill out and use the shimano plates as well. If he tried this the only thing he could use suntour would be the metal bushings, the suntour side plates wouldn't fit into the groove on the shimano wheels and probably wouldn't let the wheels turn, so he'd have to use the shimano side plates. But I think suntour wheels are generally wider than shimano so the bushings probably wouldn't mate properly in any way. The best I think he'd end up with is a shimano wheel without side plates spinning on a suntour bushing, and that would be a pretty flippity-floppity setup.