Env: JBoss AS 4.0.5.GA w/EJB3

I have looked over several different docs that describe how to use entity inheritance w/ SINGLE_TABLE. I used those examples as the basis for my code. I have a base class Units and have subclasses RFUnit and EMUnit.

(em is an entitymanager object)

When I do em.find() or em.getResultList() it always returns the base class. I get no errors of any kind. I am examining the returned class by both returnedObject.getClass().getName() and via Eclipse debugger.

Anyone: Please advise as to how to get subclasses returned from em find or query????

Here are the relevant class declarations:

// base class
@Entity
@Table(name = "units", catalog = "test2", uniqueConstraints = @UniqueConstraint(columnNames = "unitName"))
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="hwModel", discriminatorType=DiscriminatorType.INTEGER)
.....
// 1st subclass
@Entity
@DiscriminatorColumn(discriminatorType = DiscriminatorType.INTEGER)
@DiscriminatorValue(value="3")
public class RFUnit extends Units {
.....

// 2nd subclass
@Entity
@DiscriminatorColumn(name="hwModel", discriminatorType = DiscriminatorType.INTEGER)
@DiscriminatorValue(value="7")
public class EMUnit extends RFUnit {
......

// code doing find/fetch
UnitsList ul = new UnitsList(); // Seam convenience class
List l = ul.getResultList();

for (Units u:l)
{
String tmp = u.getClass().getName();
System.out.println(u.getClass().getName());
}

I also tried:

ul.getEntityManager().createQuery("Select units from Units units").getResultList(); to do the fetch. Same result.

This should be simple. What am I missing?
I did confirm the discriminator column values where as specified in the @DiscriminatorValue annotation.