How to reference Typed Dataset in codebehind (.net 4.5)

I create a new project in VS 2013 by File/NewProject and selecting .NET Framework 4.5 and ASP.Net Web Application, and then I select Web Forms.
The project is created and I then right click on the project and select Add/Add ASP.NET Folder/App_Code. I then right click on the newly add App_Code folder and select Add/DataSet.
The DataSet is created and I then right click on the designer and select Add/TableAdapter and follow the wizard to add the TableAdapter.
My problem is that when trying to reference the DataSet in codebehind, i.e.
using myDataSetTableAdapters; I get a "The type or namespace 'myDataSetTableAdapters' could not be found (are you missing a using directiveor an assemblt reference)"
How can this be resolved?
Any assistance in this regard highly appr ...