App.config file and section type in Video tutorial

I have a problem. I'm learning from MTaulty's video: http://channel9.msdn.com/blogs/mtaulty/prism--silverlight-part-2-dependency-injection-with-unity. And I have a problem with .config file which he creates at 18:00 min. There is no possibility to see what is in

     <section type=".." 

I wrote:

    type="Microsoft.Practises.Unity.Configuration.UnityConfigurationSection, Microsoft.Practises.Unity.Configuration" /> 

but it does not work. I don't have idea what is wrong. I have a mistake that VisualStudio can't load file'Microsoft.Practises.Unity.Configuration and find a file.

thanks for help!