JPA Annotation Error with OneToOne and compose PK
===

I have this relation:

    +------------------+    +----------------+    +----------+
    | TTR_AUT          |    | TTR_ANO_ESCALA |    | TTR_POA  |
    +------------------+    +----------------+    +----------+
    |#ID_ESCAL         |    |#ID_ESCAL       |    |#ID_ESCAL |
    |#ANO              |----|#ANO            |----|#ANO      |
    |#MES              |    | NOMBRE         |    |#MES      |
    | OBSERVACIONES    |    +----------------+    | VALOR    |
    +------------------+                          +----------+

TTR_AUT and TTR_POA have a oneToOne relation. And now I wont to get an object Aut with VALOR from POA. With the next entities:

**Entity Aut.java**

    @Entity
    @Table(name="TTR_AUT")
    public class Aut implements Serializable {
    	private static final long serialVersionUID = 1L;
    
    	@EmbeddedId
    	private AutPK id;
    
        @Column(name="OBSERVACIONES")
    	private String observaciones;
    
    	@OneToOne
    	@JoinTable(name="TTR_POA",
    	    joinColumns = {
    	      @JoinColumn(name="ANO", insertable=false, updatable=false, referencedColumnName="ANO"),
    	      @JoinColumn(name="ID_ESCAL", insertable=false, updatable=false, referencedColumnName="ID_ESCAL"),
    	      @JoinColumn(name="MES", insertable=false, updatable=false, referencedColumnName="MES")          
    	    },
    	    inverseJoinColumns = {
    	      @JoinColumn(name="ANO", insertable=false, updatable=false, referencedColumnName="ANO"),
    	      @JoinColumn(name="ID_ESCAL", insertable=false, updatable=false, referencedColumnName="ID_ESCAL"),
    	      @JoinColumn(name="MES", insertable=false, updatable=false, referencedColumnName="MES")
    	    }     
    	  )
    	private Poa poa;
            
        public Aut() {
        }
    
        //GETTERS AND SETTERS
    }

**Entity AutPK.java**

    @Embeddable
    public class AutPK implements Serializable {
    	//default serial version id, required for serializable classes.
    	private static final long serialVersionUID = 1L;
    
    	@Column(name="ID_ESCAL", unique=true, nullable=false, precision=22)
    	private Long idEscal;
    
    	@Column(name="ANO", unique=true, nullable=false, precision=22)
    	private Long ano;
    
    	@Column(name="MES", unique=true, nullable=false, precision=22)
    	private Long mes;
    
        public AutPK() {
        }
        
        //GETTERS AND SETTERS
    }
**Entity Poa.java**

    @Entity
    @Table(name="TTR_POA")
    public class Poa implements Serializable {
    	private static final long serialVersionUID = 1L;
    
    	@EmbeddedId
    	private PoaPK id;
    	
    	@Column(name="VALOR", precision=22)
    	private BigDecimal valor;

        public Poa() {
        }
        
        //GETTERS AND SETTERS
    }
**Entity PoaPK.java**

    @Embeddable
    public class PoaPK implements Serializable {
    	//default serial version id, required for serializable classes.
    	private static final long serialVersionUID = 1L;
    
    	@Column(name="ID_ESCAL", unique=true, nullable=false, precision=22)
    	private Long idEscal;
    
    	@Column(unique=true, nullable=false, precision=22)
    	private Long ano;
    
    	@Column(unique=true, nullable=false, precision=22)
    	private Long mes;
    
        public PoaPK() {
        }

        //GETTERS AND SETTERS
    }

When I get the object Poa, it throws this error:

    ]] Root cause of ServletException.
    java.lang.IllegalArgumentException: org.hibernate.TypeMismatchException: Provided id of the wrong type for class es.model.entities.Poa. Expected: class es.model.entities.PoaPK, got class es.model.entities.AutPK
    	at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:314)
    	at es.model.entities.dao.impl.AutDAOImpl.getAutDeterminada(AutDAOImpl.java:25)
    	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    	Truncated. see log file for complete stacktrace
    Caused By: org.hibernate.TypeMismatchException: Provided id of the wrong type for class es.model.entities.Poa. Expected: class es.model.entities.PoaPK, got class es.model.entities.AutPK
    	at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:132)
    	at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1079)
    	at org.hibernate.internal.SessionImpl.internalLoad(SessionImpl.java:1006)
    	at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:613)
    	at org.hibernate.type.EntityType.resolve(EntityType.java:441)
    	Truncated. see log file for complete stacktrace

***What's the problem/error?***