Auto-load missions in 1.4?

I had my project set so that when I clicked a button, it skipped the mission selection list and went straight into a mission that I wanted it to.

I had this in mainMenuGui.gui:

new GuiButtonCtrl() {
      profile = "GuiButtonProfile";
      horizSizing = "right";
      vertSizing = "top";
      position = "36 237";
      extent = "110 20";
      minExtent = "8 8";
      visible = "1";
      //command = "Canvas.setContent(StartMissionGUI);";  <-- original line
      command = "SM_StartMission();";        <-- changed it to this
      text = "Enter World...";
      groupNum = "-1";
      buttonType = "PushButton";
         helpTag = "0";
   };

Then at the bottom of the same file, I had:

function SM_StartMission()
{
   if ($pref::HostMultiPlayer)
      %serverType = "MultiPlayer";
   else
      %serverType = "SinglePlayer";

   createServer(%serverType, "kwm/data/missions/arlenhills.mis");
   %conn = new GameConnection(ServerConnection);
   RootGroup.add(ServerConnection);
   %conn.setConnectArgs($pref::Player::Name);
   %conn.setJoinPassword($Client::Password);
   %conn.connectLocal();
}

In 1.3 this worked fine. In 1.4 I click the button and get a loading screen, but without any mission information and it just hangs there. Did something change that prevents this from working? Or is there a better way to do this?