Trying to extend moduser... not working.

<?xml version="1.0" encoding="UTF-8"?>

<model package="extuser" baseClass="xPDOObject" platform="mysql" defaultEngine="MyISAM" version="1.1" >

    <object class="extUser" extends="modUser">
        <composite alias="UserData" local="id" class="Userdata" foreign="internalKey" cardinality="one" owner="local" />
        <composite alias="UserQueries" local="id" class="UserQueries" foreign="internalKey" cardinality="many" owner="local" />
    </object>

    <object class="UserData" table="user_ext_data" extends="xPDOSimpleObject">
        <field key="internalKey" dbtype="int" precision="10" phptype="integer" null="true" />
        <field key="location" dbtype="varchar" precision="50" phptype="string" null="true" />
        <aggregate alias="extUser" local="internalKey" foreign="id" cardinality="one" owner="foreign" />
    </object>

    <object class="UserQueries" table="user_queries" extends="xPDOSimpleObject">
        <field key="internalKey" dbtype="int" precision="10" phptype="integer" null="false" />
        <field key="date" dbtype="time" phptype="string" null="false" />
        <field key="query" dbtype="longtext" phptype="string" null="false" />
        <aggregate alias="extUser" local="internalKey" foreign="id" cardinality="one" owner="foreign" />
    </object>

</model>

$modx->addPackage('extuser', MODX_CORE_PATH . 'components/extuser/model/');

$user = $modx->getObject('extUser', 2); // where 123 is the id of a user

echo $user->get('username');

$data = $user->getOne('UserData'); // use the alias from the schema

if($data){echo 'got data<br>';}else{echo 'nodata<br>';}

//toArray will print all the extra data, e.g. facebook_url

//return print_r($data->toArray(), true);

<?php
$xpdo_meta_map['UserData']= array (
  'package' => 'extuser',
  'version' => '1.1',
  'table' => 'user_ext_data',
  'extends' => 'xPDOSimpleObject',
  'fields' => 
  array (
    'internalKey' => NULL,
    'location' => NULL,
  ),
  'fieldMeta' => 
  array (
    'internalKey' => 
    array (
      'dbtype' => 'int',
      'precision' => '10',
      'phptype' => 'integer',
      'null' => true,
    ),
    'location' => 
    array (
      'dbtype' => 'varchar',
      'precision' => '50',
      'phptype' => 'string',
      'null' => true,
    ),
  ),
  'aggregates' => 
  array (
    'extUser' => 
    array (
      'local' => 'internalKey',
      'foreign' => 'id',
      'cardinality' => 'one',
      'owner' => 'foreign',
    ),
  ),
);

$user = $modx->getObject('extUser', array('internal_key' => 2));

class extUser extends modUser {
    function __construct(xPDO & $xpdo) {
        parent::__construct($xpdo);
        $this->set('class_key', 'extUser');
    }
}

$hook->setValue('class_key', 'extUser');

<composite alias="UserData" local="id" class="Userdata" foreign="internalKey" cardinality="one" owner="local" />

$data = $user->getOne('UserData'); // use the alias from the schema