ScrollViewer manipulation

Dear all,

I have within a ScrolViewer a stack panel with two user control, each user control displays in full screen resolution.
When I touch the first control and slide it up then it display the second one. So far so good.

What I am looking for to accomplish is that if the user start to slide up the scroll viewer and then release his finger, I would like to control the scroll viewer translation up. IN similar way as the new start screen of Windows 8.1.

For that I have use the scrllchange event and run following code in it :

 private void _mainVScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
        {
            //if (e.VerticalOffset > OffSetToScroll & !IsScrolling)
            //{
                CurScrollToPos = e.VerticalOffset;

                _mainVScrollViewer.ScrollChanged -= new ScrollChangedEventHandler(_mainVScrollViewer_ScrollChanged);
                DoubleAnimation da;
                da = new DoubleAnimation(CurScrollToPos, (_appLayoutPanel.ActualHeight / _appLayoutPanel.Children.Count * (_appLayoutPanel.Children.Count - 1)), new Duration(TimeSpan.FromSeconds(2)));
                Console.WriteLine(da.From.ToString());
                Console.WriteLine(da.To.ToString());

                CubicEase be = new CubicEase();
                be.EasingMode = EasingMode.EaseInOut;
                da.EasingFunction = be;
                IsScrolling = true;
                da.Completed += new EventHandler(da_Completed);
                this.BeginAnimation(VOffsetProperty, da);

            //}
          
        }

running this is doing weird things because f I release touch the event is still called and then weird animation occurs.

Any tips?

regards