1. Download the NHibernate source and go to the “src\NHibernate“ directory
2. Copy nhibernate-configuration-2.0.xsd, nhibernate-mapping-2.0.xsd, and nhibernate-generic.xsd to the Visual Studio “schemas“ directory.  By default, the schemas directory is “C:\Program Files\Microsoft Visual Studio 8\Xml\Schemas“.
3. Restart Visual Studio

That's it.  No more hunting around and guessing what is valid NHibernate mapping or configuration xml syntax.

来自

NHibernate Sample Code