Can't replace loading image in web player

I'm having issues with replacing the load image in the unity webplayer: following the instructions in the user manual, I'm able to change the background color just fine, but it won't do a thing for the images. I have a new png named MyLogo in the same directory as the html page, and I'm using 3.5 Pro.

Here's the javascript:

         if (typeof unityObject != "undefined") {
 
 var params = {
     backgroundcolor: "A0A0A0",
     bordercolor: "000000",
     textcolor: "FFFFFF",
     logoimage: "MyLogo.png",
     progressbarimage: "MyProgressBar.png",
     progressframeimage: "MyProgressFrame.png"
 };
             unityObject.embedUnity("unityPlayer", "WebPlayer/WebPlayer.unity3d", 600, 450, params);
             
         }