How do you change the appearance of a player?

Hello, back at It again with another question. I've been trying to change the appearance of a player using player.CharacterAppearance. I want to change the appearance whenever a player presses a button to pick their class. So far I'm trying to make them Shedletsky. The script below located in a function inside of a server side script, which is repeatedly activated when fired by a remote event. The script gets the "player" from the remote event argument, player.

if num1 = 1 then
print ("the number one was chosen")
-- irrelevant things go here
player.CharacterAppearance = "http://www.roblox.com/Asset/CharacterFetch.ashx?userId=261"
-- giving the player gear and changing their walkspeed and such go here
end

I checked in the game's configuration so I can override the characters appearance already, but this seems to not be working. Are there extra steps that need to be taken before this, or is the way I am approaching it completely incorrect?

(Quick note: One thing I did try so far is turning off the CanLoadCharacterAppearance property when a player joins, but that did absolutely nothing so I got rid of it. Was that necessary?)