Oh. I was kinda hoping that this was a better solution than what I have at the moment.Catapults don't work in multiplayer
IFLOLS work by moving the joystick up and down, call the ball.
I have gotten the entire Acceleration carrier to work in multiplayer (catapults and all) as a multiplayer mission. The only bad thing about that solution is that once a session is started, you can only join as an Observer and as Observer, people can't see you. I've got a concept for better solution, but I've got to do some work on it. It's a great solution if you're with a friend and want to play together, though. You can get the mission here: http://www.fswaterconfigurator.com/downloads.htm.