JPA...tabela associativa como chave PK....?Duvida

Olá,duvida

referente a uma tabela associativa (manytomany) criada através da classe

e ficou assim

[code]

CREATE TABLE employer_employee (
EMPER_ID int(11) NOT NULL,
EMPEE_ID int(11) NOT NULL,
KEY FKDC9B93B29245299A (EMPEE_ID),
KEY FKDC9B93B2924B127A (EMPER_ID),
CONSTRAINT FKDC9B93B2924B127A FOREIGN KEY (EMPER_ID) REFERENCES employer (EMPER_ID),
CONSTRAINT FKDC9B93B29245299A FOREIGN KEY (EMPEE_ID) REFERENCES employee (EMPEE_ID)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

[/code}

minha duvida queria que cada campo fosse PK pois estou vendo acima que somente
está KEY …

no MYSQL é assim mesmo ???

se alguém puder me ajudar agradeceria…

abs

import java.io.Serializable;
import java.util.Collection;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;


@Entity
@Table
public class Employer implements Serializable {

    @Id
    @Column(name="EMPER_ID")
    private int id;
    @ManyToMany(
        targetEntity=Employee.class,
        cascade={CascadeType.PERSIST, CascadeType.MERGE}
    )
    @JoinTable(
        name="EMPLOYER_EMPLOYEE",
        joinColumns=@JoinColumn(name="EMPER_ID"),
        inverseJoinColumns=@JoinColumn(name="EMPEE_ID")
    )
    
    private Collection<Employee> employees;
    
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public Collection<Employee> getEmployees() {
		return employees;
	}
	public void setEmployees(Collection<Employee> employees) {
		this.employees = employees;
	}
    
   
    
}
-----
@Entity
@Table
public class Employee implements Serializable {
	@Id
	@Column(name="EMPEE_ID")
	private int id;
    @ManyToMany(
        cascade = {CascadeType.PERSIST, CascadeType.MERGE},
        mappedBy = "employees",
        targetEntity = Employer.class
    )
    private Collection<Employer>  employers;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public Collection<Employer> getEmployers() {
		return employers;
	}
	public void setEmployers(Collection<Employer> employers) {
		this.employers = employers;
	} 
    
    
}