Take him hunting with another dog.. It should come natural and if not the other hunting dog will put it in it's place.. I have a fushing Irish Setter which I use mostly for locating birds.. I also have a pointing Irish Setter that I use as my main gun dog.. The flushing irish setter will stop and go on point as long as my pointer is pointing..
This was completely without any sort of training on the flusher.. It was a natural instinct. I also feel my pointer would clearly warn it if it was to react in any other way..So to get them to honor another pointing dog IMO is to find a hunter who wouldn't mind having you and your dog to tag along..