Since i cant find a video for this i will have to explain it. After you beat red on SSHG the first time if you want to battle him again the only way he will appear on mount silver again is if you go back to the pokemon league and beat the elite four again. He will then show up on mount silver and you can battle him. To keep on battling him over and over you must continue on by defeating the elite four again and all that good stuff.