Linq to Nhibernate question

Question

Consider this 3 classes

public class ClassA
{
     public IList<ClassB> BList {get; private set;}
}

public class ClassB
{
    public ClassC C {get; private set;}
}

public ClassC
{
   //doesn't matter
}

I want to get all ClassA instances from the repository, that has at least one BList element containing a specific C instance, that i pass to the repository:

public IList<ClassA> GetAllAContainingC(ClassC parameterC)

i used Linq To Nhibernate to obtain this list:

        var query = Session.Linq<ClassA>().Where(a => a.BList.Count(b => b.C.Equals(parameterC)) > 0);

        return query.ToList();

The compiler accepts this. But when i run the test NHibernate throws this exception:

NHibernate.QueryException: could not resolve property: C of: ClassA

But the thing is, C is property of B, and in that lambda in the context where I call C, its being accessed from a B, (even the intelissense lists that property).

Can anyone explain me what i am doing wrong? Thank you