Polymorphic CriteriaQuery without inverse relationship

I have the following EJB structure. Don't wonder about Animal and Inventory, these classes are only here to demonstrate the structure in a simplified way (Update: I have revised the class names to construct a better understandable example. Another implementation of IdTag might be a BarcodeId). Note that there is no inverse relationship from IdTag to Animal or Inventory, and let's assume the RfidTag.code is unique. I read Retrieving Polymorphic Hibernate Objects Using a Criteria Query and Hibernate polymorphic query but these discussions does not seem to answer my question.

public interface ItemWithIdTag
{
    IdTag getIdTag();
    void setIdTag(IdTag idTag);
}

@Entity public class Animal implements ItemWithIdTag,Serializable
{
    @Id @GeneratedValue(strategy=GenerationType.AUTO) private long id;

    @OneToOne(cascade = CascadeType.ALL)
    private IdTag idTag;
}

@Entity public class Inventory implements ItemWithIdTag,Serializable
{
    @Id @GeneratedValue(strategy=GenerationType.AUTO) private long id;

    @OneToOne(cascade = CascadeType.ALL)
    private IdTag idTag;
}

@Entity @Table(name = "IdTag") @Inheritance(strategy= InheritanceType.JOINED)
public class IdTag implements Serializable
{
    @Id @GeneratedValue(strategy=GenerationType.AUTO) private long id;
    private Date created;
}

@Entity @Table(name = "RfidTag")
public class RfidTag extends IdTag implements Serializable
{
    private String code;
}

Now I want to query either Animal or Inventory for a given RfidTag.code like Animal ejb = bean.fEntityWithRfidTag(Animal.class,"myRfIdCode");

public <T extends ItemWithIdTag> T fOwner(Class<T> type, String catNam