How to add NHibernate XML schema to Visual Studio?

I'm learning NHibernate and I added <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> to App.config. Visual Studio reported a message:

Could not find schema information for the element 'urn:nhibernate-configuration-2.2:hibernate-configuration'.

I know this is not a problem, but if VS knew the schema, IntelliSense would work. How can I add the schema?

How do I import XSD files into Visual Studio?

You can easily just add an existing XSD on disk to your Visual Studio project by doing a "Add Existing Item" and then picking that file. There's no separate "import / export" functionality, really.

Just include the XSD files in any of your projects or as Solution Items.