Given a simplified model like the following:

public class Enquiry
{
    public virtual DateTime Created { get; set; }
    public virtual Sender Sender { get; set; }
}

public class Sender
{
    public virtual IList<Enquiry> Enquiries { get; set; }
}

How can you construct a Linq to Nhibernate query such that it gives you back a list of senders and their enquiries where the enquiries meet some criteria. I have tried something like this:

return session.Linq<Enquiry>()
   .Where(enquiry => enquiry.Created < DateTime.Now)
   .Select(enquiry => enquiry.Sender)

In this case I get an InvalidCastException saying you can't cast type Sender to type Enquiry.

Any pointers on how I can do this without using HQL?