I have a SharePoint 2010 Solution that is made in VS 2012. I wanted to try and upgrade the solution to it deploy to our new SharePoint 2013 server.
In the Package properties i have set the version to 15.0

The site url is pointing to the SP2013 site collection.

But the Server Connection is giving me the following error.

Also, the Project Properties, wont let me choose .NET Framework 4.0

How can i get VS2012 to treat the project as if it is a SharePoint 2013 Solution ?