Storyboard loading from extrnal file

I've external xaml file witch scene,cameras and storyboard everything is warped witch <Viewport3D>....</Viewport3D>.

I'm loading my model.xaml file with

                try
                {
                    StreamReader mysr = new StreamReader(path);
                    _grid.Children.Add(XamlReader.Load(mysr.BaseStream) as Viewport3D);
                }
                catch

And i want to start my application using button

private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            Storyboard sb = this.FindResource("MoveSB") as Storyboard;            
            sb.Begin();
        }

but visual can't find my resource normally i would write  this.myViewPort.FindResource("MoveSB") as Storyboard; 

I probably have to call it in different way but have no idea how.