Web services

Hi,

I've created a new external function which should enrol a user into a course.
The problem is that it does not get recognized?!
It is not listed in the list of functions I can add to specific webservice. It is not in the database either.

What am I doing wrong?

here is my code:
added to /lib/db/services.php
[code]
'moodle_enrol_set_manual_enrol' => array(
'classname' => 'moodle_enrol_external',
'methodname' => 'set_manual_enrol',
'classpath' => 'enrol/externallib.php',
'description' => 'Manual enrol users into a course',
'type' => 'write',
'capabilities'=> 'enrol/manual:enrol',
),
[/code]

added to /enrol/externallib.php
[code]
/**
* Returns description of method parameters
* @return external_function_parameters
*/
public static function set_manual_enrol_parameters() {
return new external_function_parameters(
array(
'userid' => new external_value(PARAM_INT, 'ID of user'),
'courseid' => new external_value(PARAM_INT, 'The course id where all users should be enroled to'),
)
);
}

/**
*
* Enrol users into a course
* @param array $userids An array of user ids
* @param int $course_id ID of course
*/
public static function set_manual_enrol($userid, $courseid) {

$params = self::validate_parameters(self::enrol_manual_parameters(), array('userid'=>$userid, 'courseid'=>$courseid));

$instance = $DB->get_record('enrol', array('id'=>1, 'enrol'=>'manual'), '*');
$instance->courseid = $course_id;

if (!$enrol_manual = enrol_get_plugin('manual')) {
throw new coding_exception('Can not instantiate enrol_manual');
}

$timestart = time();
$timeend = 0;

$enrol_manual->enrol_user($instance, $userid, $roleid, $timestart, $timeend);
}

/**
* Returns description of method result value
* @return external_description
*/
public static function set_manual_enrol_returns() {
return null;
}
}
[/code]

I hope somebody can help me. Thanks.