Issue with one-to-one and PropertyReference

[codemonkey]

Why does it do this check in PropertyReference in the OneToOneMapper:

if (this._member != null && propertyInTheOtherSide.DeclaringType != this._member.GetPropertyOrFieldType())
            {
                throw new ArgumentOutOfRangeException("propertyInTheOtherSide", string.Format("Expected a member of {0} found the member {1} of {2}", this._member.GetPropertyOrFieldType(), propertyInTheOtherSide, propertyInTheOtherSide.DeclaringType));
            }

I have classes like so:

public class Owner {

    public Foo1 Foo1 {get;set;}

    public Foo2 Foo2 {get;set;}

}

public class Foo {

    public Owner Owner {get;set;}

}

public class Foo1 : Foo {

}

public class Foo2 : Foo {

}

I then have a mapping for Owner with a OneToOne like so:

OneToOne(x => x.Foo1, m =>

            {

                m.Cascade(Cascade.All);

                m.PropertyReference<Foo1>(x => x.Owner);

            });

This throws the exception, the only way I could get it to work is add an override for Owner to Foo1 and Foo2 like so and ignore the Owner property in the Foo1 and Foo2 mappings:

public class Foo1 {

    public Owner Owner {
        get { return base.Owner; }

        set { base.Owner = value; }

    }

}

Is there a better way to get around this *hack*?

Cheers