Querying Many To Many associations using the Criteria API

Ayende as just posted about querying many to many associations using Criteria. Here's how:

DetachedCriteria blogAuthorIsJosh = DetachedCriteria.For<User>()
.Add(Expression.Eq("Username", "josh")
.CreateCriteria("Blogs", "userBlog")
.SetProjection( Projections.Id())
.Add(Property.ForName("userBlog.id").EqProperty("blog.id"));

DetachedCriteria categoryIsNh = DetachedCriteria.For(typeof(Category),"category")
 .SetProjection(Projections.Id())
 .Add(Expression.Eq("Name", "NHibernate"))
 .Add(Property.ForName("category.id").EqProperty("postCategory.id "));

session.CreateCriteria(typeof (Post),"post")
 .CreateAlias("Categories", "postCategory")
 .Add(Subqueries.Exists(categoryIsNh))
 .CreateAlias("Comments", "comment")
 .Add(Expression.Eq("comment.Name", "ayende"))
 .CreateAlias("Blog", "blog")
 .Add(Subqueries.Exists(blogAuthorIsJosh))
 .List();

I had already tried it but with no results. Looks like a refactoring week is approaching for me if I can get it to work over our HBMs :)