silverlight Storyboard begin from end of time with AutoReverse is true

Storyboard sbSongName = (Storyboard)this.FindResource("sbSongName");
sbSongName.Stop();
sbSongName.AutoReverse = true;
sbSongName.Begin();
sbSongName.SeekAlignedToLastTick(sbSongName.GetCurrentTime(), TimeSeekOrigin.Duration);