LoadLevelAsync movie not playing gui!!

hi i am having problem with making loading screen while the level loads in the background. i am using loadlevelasync function. but the problem is i also have a loading movie, and a loading background image, the images show as planned, however the movie is not playing.

i think the problem is that the level loads before the movie gets any chance to play. so how to solve this, i want to play the movie as loading the level in bg and when the loading is done, it switches to the loaded level.

i am using GUI box to show images and play the movie. here is my code,

 var skin:GUISkin;
 public var guiDepth : int = 0;
 var image: Texture2D;
 public var backgroundaudio: AudioClip;
 public var PlayVid : MovieTexture;
 
 function Start () {
         // Load the level named "MyBigLevel".
         var async : AsyncOperation = Application.LoadLevelAsync ("round1");
         yield async;
         Debug.Log ("Loading complete");
     }
    
     function OnGUI()
     {
 GUI.depth = guiDepth;
 GUI.Box(Rect (0,0,Screen.width,Screen.height), image);
 
 
        PlayVid.loop = true;
        PlayVid.Play();
     GUI.DrawTexture(Rect (Screen.width - 260,Screen.height - 110,260,110), PlayVid);
 
 }