Spring data JPA using Entity Type expression

I would like to use the JPA 2.0 Type expression in a spring data JPA repository @Query but it give me a validation error Validation failed for query for method public abstract java.util.List my.org.FooRepository.findAllByRoomCode()!.

Here is my entities definition :

inherited :

@Entity(name = "Location")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class LocationEntity {

    @Column(name = "CODE")
    protected String code;

    @OneToMany(mappedBy = "location")
    protected List<LampEntity> lamps = new ArrayList<LampEntity>();
        ...
}

@Entity(name = "Floor")
@Table(name = "FLOOR", uniqueConstraints = {
    @UniqueConstraint(name = "FLOOR_UK", columnNames = "CODE")
})
public class FloorEntity extends LocationEntity {
    ...
    @OneToMany(mappedBy = "floor")
    private List<RoomEntity> rooms = new ArrayList<RoomEntity>();
    ...
}

@Entity(name = "Room")
@Table(name = "ROOM", uniqueConstraints = {
    @UniqueConstraint(name = "ROOM_UK", columnNames = { "CODE", "FLOOR_ID" })
})
public class RoomEntity extends LocationEntity {
    ...
    @ManyToOne
    @JoinColumn(name = "FLOOR_ID", nullable = false, referencedColumnName = "ID")
    private FloorEntity floor;
    ...
}

requested entity :

@Entity(name = "Lamp")
@Table(name = "LAMP")
public class LampEntity {

    @ManyToOne
    @JoinColumn(name = "LOCATION_ID", referencedColumnName = "ID")
    private LocationEntity location;
}

repository :

public interface LampRepository extends JpaRepository<LampEntity, Long> {

    @Query("SELECT lamp FROM Lamp lamp WHERE lamp.location.code = :locationCode AND TYPE(lamp.location) = Room")
    public List<LampEntity> findAllByRoomCode(@Param("code") String locationCode);
    ...
}

I'm using spring-data-JPA 1.4.1.RELEASE with Hibernate 4.2.7.Final as provider.

My questions are :

1. Is it possible to do that with Spring data JPA ?
2. In a old stackoverflow post i saw that Hibernate accepted it only with InheritanceType.SINGLE_TABLE but maybe now it's ok in 4.2.7 ?
3. If not, what are my alternative if I want to keep my InheritanceType.TABLE_PER_CLASS strategy ?

Thanks a lot

Updated with unique constraints and relation between Floor and Room