Creating reference in node-mongodb-native

ref.js

var mongo = require('../lib/mongodb'),
    sys = require('sys');

    var host = process.env['MONGO_NODE_DRIVER_HOST'] != null ? process.env['MONGO_NODE_DRIVER_HOST'] : 'localhost';
    var port = process.env['MONGO_NODE_DRIVER_PORT'] != null ? process.env['MONGO_NODE_DRIVER_PORT'] : mongo.Connection.DEFAULT_PORT;

sys.puts("Connecting to " + host + ":" + port);
var db = new mongo.Db('test', new mongo.Server(host, port, {}), {});
db.open(function(err, db) {
    db.collection('players', function(err, collection) {
        collection.findOne({"name":'kze'}, function(err, player){
/*            db.dereference(player.tank, function(err, tank) {
                sys.puts('Player ' + player.name + ' tank speed is ' + tank.speed);
            });*/
        collection.insert({'name':'dark', 'identity': new mongo.DBRef('players', player._id)}
, function(err) { sys.puts('Reference inserted: ' + JSON.stringify(err))});

        });
    });
});