title: Pushpin is null
body: <p>I have a map with 2 Pushpins, when I load the page, I am setting the location of one of the pushpins in the code behind. However, when I try to reference the pin, it is null.</p>
  
  <p>XAML</p>
  
  <pre><code> &lt;maps:Map x:Name="mapEventLocation" ZoomLevel="15" Grid.Row="1" Tap="mapEventLocation_Tap" &gt;
          &lt;maptoolkit:MapExtensions.Children&gt;
              &lt;maptoolkit:Pushpin x:Name="userLocationPin" Content="You" Visibility="Collapsed" /&gt;
              &lt;maptoolkit:Pushpin x:Name="eventLocationPin" Content="Event" Visibility="Collapsed" /&gt;
          &lt;/maptoolkit:MapExtensions.Children&gt;
      &lt;/maps:Map&gt;
  </code></pre>
  
  <p>C#</p>
  
  <pre><code>    private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
      {
          if (this.NavigationContext.QueryString.ContainsKey("lat"))
          {               
              userLocationPin.GeoCoordinate = new GeoCoordinate(double.Parse(this.NavigationContext.QueryString["lat"]), double.Parse(this.NavigationContext.QueryString["lon"]));
              userLocationPin.Visibility = System.Windows.Visibility.Visible;
              mapEventLocation.Center = new GeoCoordinate(double.Parse(this.NavigationContext.QueryString["lat"]), double.Parse(this.NavigationContext.QueryString["lon"]));
          }
      }
  </code></pre>
  
  <p>Lat and Lon are definitely in the QueryString.</p>
  
  <p>Before this, used </p>
  
  <pre><code>Pushpin pin = (Pushpin)this.FindName("userLocationPin");
  </code></pre>
  
  <p>That works for the emulator, but not on the real phone.</p>
  
  <p>I have tried to make the Pushpins manually in a layer, but the pin goes off to the corner</p>
  
  <pre><code>Pushpin userLocation = new Pushpin();
  userLocation.GeoCoordinate = new GeoCoordinate(double.Parse(this.NavigationContext.QueryString["lat"]), double.Parse(this.NavigationContext.QueryString["lon"]));
  userLocation.Content = "You";
  MapLayer layer = new MapLayer();
  MapOverlay overlay = new MapOverlay();
  overlay.Content = userLocation;
  layer.Add(overlay);
  mapEventLocation.Layers.Add(layer);
  </code></pre>
  
  <p>Any ideas would be greatly appreciated.
  Thanks</p>