Namespace autoloating

I've created a config item for autoloading namespaces:

   'additionalNamespaces' => array(
        'Voice' => __DIR__ . '/../../app/library/' . '/Voice',
        'Phalcon' => array(
            '/Users/stephenhoogendijk/phalcon-incubator/Library/Phalcon',
            __DIR__ . '/../../app/library/' . '/Phalcon'
        )
    )

/**
 * Load additional namespaces from the config if there any present
 */
if(is_array($config->additionalNamespaces)) {

    $loader->registerNamespaces(
        $config->additionalNamespaces
    );
}

But it doesn't seem to take, can't you define namespaces in multiple directories?

The reason we are doing this is because we want to define our own components in the library dir under /phalcon before making a pull request for the incubator.