using Symfony class loader

Recently, I'm diving into symfony's class loader component. However, I need to solve an issue. I have the following folder structure;

-> project
    -> public
        -> index.php
    -> package
        -> Request.php

In index.php I'm using the following statements to load the class loader of Symfony;

define ('ROOT', dirname(dirname(__FILE__)));

$paths = array(
    'system' => ROOT . '/package'
);

$namespaces = array(
    'MyNamespace' => $paths['system']
);

require $paths['vendor'] .
    '/symfony/class-loader/Symfony/Component/ClassLoader/UniversalClassLoader.php';

use Symfony\Component\ClassLoader\UniversalClassLoader;

$autoload = new UniversalClassLoader();
$autoload->registerNamespaces($namespaces);
$autoload->register();

use MyNamespace\Request;

Request::create();

In Request.php, I have the following code;

namespace MyNamespace;

class Request
{
    static public function create()
    {

    }
}

However, in index.php file, It says that Request class can't be found

So, What am I doing wrong here ? Any ideas ?