Problem getting something "above" a Google Earth plugin

I'm trying to reorder elements on a page, so that my Silverlight appears above the GE plugin rather than below it.

Here's the HTML code:

<form id="form1" runat="server" style="height:100%">
<div id="silverlightControlHost" style="position:absolute;top:0px;left:0px;bottom:0px;right:0px;background-color:transparent;z-index:9999999">
    <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
      <param name="source" value="ClientBin/GoogleEarthApiTest.xap"/>
      <param name="onError" value="onSilverlightError" />
      <param name="background" value="white" />
      <param name="minRuntimeVersion" value="4.0.50826.0" />
      <param name="autoUpgrade" value="true" />
      <param name="windowless" value="true" />
      <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none">
          <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/>
      </a>
    </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe></div>
<div id="map3d" style="position:absolute;left:100px;top:100px;bottom:0px;right:0px;z-index:-1"></div>
</form>

I thought adding the z-index style property would suffice, but the GE is still rendered above the SL application (in both the latest Firefox and IE).

I suspect I'm missing something obviou开发者_运维百科s here. What could it be?

If you don't need anything to appear above the silverlight control change its windowless param to false.

I ended up hiding the Google Earth div when I wanted to display anything "over" it. :/