Get ListViewItem DataTemplate when a ItemTemplateSelector is used

Question

I have a ListView where I use a ItemTemplateSelector. Inside my DataTemplate is a MediaElement. I want to be able to start/pause the Video when I click on the ListViewItem. I have the following Code so far:

private void ListViewItem_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        var item = sender as ListViewItem;
        ContentPresenter contentPresenter = UIMGR.UIHelper.GetVisualChild<ContentPresenter>(item);
        DataTemplate myDataTemplate = contentPresenter.ContentTemplate;
        MediaElement myMediaElement = (MediaElement)myDataTemplate.FindName("meSender", contentPresenter);
        if(myMediaElement != null)
        {

        }
    }

But my ContentTemplate is null. How can I access the DataTemplate of my ListViewItem?