How do I add VisualStateManager to my Surface project?

I 开发者_Go百科have a surface project and I would like to use controls designed in Blend. I added these controls to my microsoft surface project, but I receive an error when I try to compile it.

Error 1 The tag 'VisualStateManager.VisualStateGroups' does not exist in XML namespace
'http://schemas.microsoft.com/winfx/2006/xaml/presentation'. Line 12 Position 4.
UserControl1.xaml 12 4  

How can I solve this issue? Can I use the VisualStateManager in Surface application at all?

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Make sure you are

• using WPF 4
• OR using the WPF Toolkit (http://wpf.codeplex.com/)

VSM is not built into WPF before 4.