EF Navigation Property with null foreign key

Question

I'm attempting to use navigation properties for the first time in lieu of doing joins. I cannot get a situation to work where it would normally be done with a left outer join. In the following example, I'm only getting results back where the foreign key is non-null. I need all results back. What am I missing?

public class User
{
    [Key]
    public int UserID {get;set;}

    public String Name {get;set;}
}

public class Shipment
{
    [Key]
    public int ShipmentID {get;set;}

    public int? SignedForByID {get;set;}

    [ForeignKey("SignedForByID")]
    public virtual User SignedForBy{get;set;}
}

navigation property mapping:

 Shipment.HasOptional(x=> x.SignedForBy).WithMany()
.HasForeignKey(y=> y.SignedForByID).WillCascadeOnDelete(false);

query:

var data = (from s in context.Set<Shipment>()
            select new {
                    ShipmentID = s.ShipmentID,
                    SignedForBy = s.SignedForBy
                        });

Answer 1

The problem was not shown in this example. The mappings are generated by a helper class. In some cases, the helper class incorrectly mapped the navigation properties with the .HasRequired() method instead of the .HasOptional(). Correcting the mapping class has fixed the issue.