The previous example just shows how to combine a spatial criterion (Contains) with a normal criterion (Not), but in this case we could use simply Disjoint.
Note: For people with a GIS backgroud, the "projection" term could be confusing. In this context, it has nothing to do with cartographic projections. It's rather a term borrowed from relational algebra.
You also will find lots of sample usage code in the tests project (Tests.NHibernate.Spatial). Check out: