I tried lastest Mitch version (for 1.0) and it still doesn't work..

Code:
CodeCallback_StartGameType() 
{ 
    // If the gametype has not beed started, run the startup 
    if(!isDefined(level.gametypestarted) || !level.gametypestarted) 
    { 
        disableGlobalPlayerCollision(); 
        [[level.callbackStartGameType]](); 

        level.gametypestarted = true; // so we know that the gametype has been started up 
    } 
}