I can't seem to get an EntityManager persisted automatically in a @Stateless EJB... any help appreciated.

TService.java

package tester;

import org.jboss.annotation.ejb.Management;
import org.jboss.annotation.ejb.Service;

@Service (objectName="testingt:service=testingt")
@Management(TServiceInterface.class)
public class TService implements TServiceInterface {

 public void doSomething() {
 TestEntityManager tem = new TestEntityManager();
 tem.listEntities();

 }

}

package tester;

import java.util.List;

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

@Stateless
public class TestEntityManager implements TestEntityManagerInterface {

 @PersistenceContext(unitName="Tester")
 EntityManager em;

 public List listEntities() {
 Query query = em.createQuery("from TestEntity testEntity");
 return query.getResultList();
 }
}

package tester;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="testentity")
public class TestEntity implements Serializable {

 public static final long serialVersionUID = 1L;

 private Integer id;
 private String name;

 public void setId(Integer id) {
 this.id = id;
 }

 @Id(generate=GeneratorType.AUTO)
 @Column(name="id")
 public Integer getId(){
 return this.id;
 }

 public void setName(String name) {
 this.name = name;
 }

 @Column(name="name")
 public String getName(){
 return this.name;
 }
}

<?xml version="1.0" encoding="UTF-8"?>
<entity-manager>
 <name>Tester</name>
 <provider>org.hibernate.ejb.HibernatePersistence</provider>
 <jta-data-source>java:/DefaultDS</jta-data-source>
 <properties>
 <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
 <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
 </properties>
</entity-manager>