I have set up a simple test demenstrating the issue.

http://qa-www.nbclearn.com/as3/componentsAOD2/OSMF_Simple_test.html

On this page the Wmode is set to transparent.  On the Mac If you view the page in Firefox, the video is above the test object.  If you view the page in Google Chrome or Safari on the Mac

The test object is above the video window.  IE9 on the PC also shows the stage video active below the test object.

i've inlcuded a trace statment showing weather stage video is avilable or not.

Please see my source code below for this example.

Thank you.

package

{

          import flash.display.MovieClip;

          import flash.net.URLLoader;

          import org.osmf.media.MediaElement;

          import org.osmf.media.MediaPlayerSprite;

          import org.osmf.media.MediaPlayer;

          import org.osmf.media.DefaultMediaFactory;

          import org.osmf.display.ScaleMode;

          import org.osmf.media.URLResource;

          import org.osmf.events.MediaFactoryEvent;

          import com.akamai.stagevideo.StageVideoHelper;

          import flash.events.StageVideoAvailabilityEvent;

          import flash.geom.Rectangle;

          import flash.events.Event;

          import flash.net.URLRequest;

          /**

           * ...

           * @author Ari Oshinsky

           */

          public class OSMF_Simple_test extends MovieClip

          {

                    private static const AKAMAI_PLUGIN:String =          "AkamaiAdvancedStreamingPlugin2.7_osmf1.6.swf";

                    private var videoPlayerOSMF:MediaPlayer;

                    var mediaFactory:DefaultMediaFactory;

                    var video_helper:StageVideoHelper;

                    var mediaPlayerSprite:MediaPlayerSprite

                    public function OSMF_Simple_test() {

                              mediaPlayerSprite = new MediaPlayerSprite();

                              mediaPlayerSprite.x = 5;

                              mediaPlayerSprite.y = 5;

                              mediaPlayerSprite.width = 640;

                              mediaPlayerSprite.height = 480;

                              this.addChild(mediaPlayerSprite);

                              mediaPlayerSprite.scaleMode = ScaleMode.LETTERBOX;

                    //          videoPlayerOSMF = mediaPlayerSprite.media;

                              mediaFactory = new DefaultMediaFactory()

                              mediaFactory.addEventListener(MediaFactoryEvent.PLUGIN _LOAD, onPluginLoad)

                              var resource:URLResource = new URLResource(AKAMAI_PLUGIN);

                              mediaFactory.loadPlugin(resource);

                    }

                    private function onPluginLoad(e:MediaFactoryEvent){

                              trace("~Akamai plugin loaded successfully.");

                              video_helper = new StageVideoHelper(this.stage, new Rectangle(mediaPlayerSprite.x, mediaPlayerSprite.y, mediaPlayerSprite.width, mediaPlayerSprite.height));

                              this.stage.addEventListener(StageVideoAvailabilityEven t.STAGE_VIDEO_AVAILABILITY , checkStageVideoAvilability);

                              var akamaiLoader:URLLoader = new URLLoader();

                              akamaiLoader.addEventListener(Event.COMPLETE, loadVideoStream);

                              akamaiLoader.load(new URLRequest(AKAMAI_SMIL_F4M));

                    }

                    private function loadVideoStream(event:Event) {

                              var loader:URLLoader = URLLoader(event.target);

                              var akamaiMediaResource:URLResource = new URLResource(loader.data)// the loader returns the phyisical location of the smil file.

                              var mediaElement:MediaElement = mediaFactory.createMediaElement(akamaiMediaResource);

                              mediaPlayerSprite.media =  mediaElement; // set the media element as the new media to load,  it should automaticly trigger a play command.

                    }

                    private function checkStageVideoAvilability(event:StageVideoAvailabilityEvent) {

                              object_mc.trace_txt.text = "Stage Video Available: " + event.availability;

                    }

          }

}