Java MongoDB Morphia: find a object by ObjectId id

I am using Morphia and a DAO Class. I have a Class with an Id ObjectId:

@Entity
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class GeoProfileVo extends ResponseVo implements Serializable{

    private static final long serialVersionUID = -4975628041316056892L;

    @Id private ObjectId id;

    private String email;
    private String name;
    private String city;

    //Getters, Setters and toString
}

GeoProfileDAO:

public class GeoProfileDAO extends BasicDAO<GeoProfileVo, ObjectId>{

    public GeoProfileDAO(Morphia morphia, MongoClient mongoClient, String db) {
        super(mongoClient, morphia, db);
    }

    public GeoProfileVo findByNme(String name){
        return getDs().find(GeoProfileVo.class, "name", name).get();
    }

    //Here is the problem
    public GeoProfileVo findById (ObjectId id){
        //return getDs().find(GeoProfileVo.class).field("id").equal(id).get();
        return getDs().get(GeoProfileVo.class, id);
    }

    public ObjectId saveGeoProfile(GeoProfileVo geoProfileVo){
        return (ObjectId) getDs().save(geoProfileVo).getId();
    }
}

My Service:

public class GeolocationService implements Serializable{

    private static final long serialVersionUID = 2071937170723089158L;

    /** The Constant log. */
    private static final Logger LOGGER = Logger.getLogger(GeolocationService.class.getName());

    private MongoClient mongoClient;
    private GeoProfileDAO geoProfileDAO;

    public GeolocationService(){
        super();
        LOGGER.info("[GeolocationService - Constructor] - init");

        //mongoClient:
        mongoClient = new MongoClient("localhost",27017);

        //morphia:
        Morphia morphia = new Morphia();
        morphia.map(GeoProfileVo.class);

        //morphia dao:
        geoProfileDAO = new GeoProfileDAO(morphia, mongoClient, "mydb");
    }

    public GeoProfileVo updateGeoProfile(GeoProfileVo geoProfileVo) throws GeoProfileNotFoundException{
        LOGGER.info("[GeolocationService - updateGeoProfile] - init");
        long currentSystemTime=System.currentTimeMillis();

        if(geoProfileVo == null){
            LOGGER.error("[GeolocationService - updateGeoProfile] - geoProfileVo cannot be null");
            throw new IllegalArgumentException();
        }
        if(geoProfileVo.getId() == null){
            LOGGER.error("[GeolocationService - updateGeoProfile] - ID cannot be null");
            throw new IllegalArgumentException();
        }

        GeoProfileVo geoProfileVoEntity = geoProfileDAO.findById(geoProfileVo.getId());
        if(geoProfileVoEntity==null){
            LOGGER.error("[GeolocationService - updateGeoProfile] - geoProfileVo not found in BD");
            throw new GeoProfileNotFoundException();
        }

        LOGGER.debug("[GeolocationService - updateGeoProfile] - Finish Timing:"+(System.currentTimeMillis()-currentSystemTime));
        return geoProfileDAO.updateGeoProfile(geoProfileVo);
    }

    //CRUD

}

I am able to search by email, name or city, insert a object in BD but I am not able to search by id. In google I only find information about a String id and I don´t find much information about id type ObjectId. when I try to find by the ObjectId Id, doesn´t find nothing and returns null.

For example, when I find by email, returns:

{
    geoProfileVo:{
   "id":    {
      "timestamp": 1432028968,
      "machineIdentifier": 9913253,
      "processIdentifier": 7516,
      "counter": 8215016
   },
   "email": "aaa@gmail.com",
   "name": "john",
   "email": "Madrid"
  }

I call a WS that call a createGeoProfile Service with the same Object with the same id but in Eclipse IDE, the "id" is different in each call. Maybe the problem is here but I don´t understand it.

How do I find an object with id type ObjectId?