title: Bing maps polygon/polyline appears beneath image overlay
body: <p>I´ve been following this post about using an image overlay for bing maps:</p>
  
  <pre><code>http://blogs.msdn.com/b/bingdevcenter/archive/2014/04/04/image-overlays-with-bing-maps-native.aspx
  </code></pre>
  
  <p>What I want to now is to be able to add polygons/polylines on top of this image. Lets say for example that we use the following code:</p>
  
  <pre><code>(From here: http://blogs.bing.com/maps/2014/01/23/make-clickable-shapes-in-the-native-bing-maps-control/)
  
  
  private void MyMapLoaded(object sender, RoutedEventArgs e)
  {
  //Add a shape layer to the map
      shapeLayer = new MapShapeLayer();
      MyMap.ShapeLayers.Add(shapeLayer);
  
  //Create mock data points
      var locs = new LocationCollection();
  
      locs.Add(new Location(coordinates that are over the image));
      locs.Add(new Location(coordinates that are over the image));
      locs.Add(new Location(coordinates that are over the image));
  
  //Create test polygon
      var polygon = new MapPolygon();
      polygon.Locations = locs;
      polygon.FillColor = Colors.Red;
  
  
      shapeLayer.Shapes.Add(polygon);
  
      var locs2 = new LocationCollection();
      locs2.Add(new Location(20, 20));
      locs2.Add(new Location(40, 40));
      locs2.Add(new Location(50, 20));
  
  //Create test polyline
      var polyline = new MapPolyline();
      polyline.Locations = locs2;
      polyline.Width = 5;
      polyline.Color = Colors.Blue;
  
  
  
  //Add the shape to the map
      shapeLayer.Shapes.Add(polyline);
  }
  </code></pre>
  
  <p>The problem is that the polygon/polyline will always appear beneath the image. 
  ShapeLayer has a property for z-index but it does not help. Is there a way for my polygons to always be on top?</p>