Permalink of Custom Post Type

Question

I am trying to create a custom post type called an 'event' and have it's permalink structure be as follows:

www.domain.com/events/238

where 238 is the post ID. However, when I navigate to the page, I get a 'no results found' page.

Here is my code (I abbreviated the register_post_type call to include only the important elements).

add_action( 'init', 'initialize'));

function initialize() {
    register_post_type('event',
        array(
            'labels' => array('name' => 'Events'),
            'public' => true,
            'publicly_queryable' => true,
            'query_var' => true,
            'rewrite' => false,
            'show_ui' => true,
            'has_archive' => true
        )
    );

    global $wp_rewrite;

    $event_structure = '/events/%event_id%';
    $wp_rewrite->add_rewrite_tag("%event_id%", '([0-9]+)', "event_id=");
    $wp_rewrite->add_permastruct('event', $event_structure, false);
}

add_filter('post_type_link', 'handle_permalink', 10, 3);

function handle_permalink( $permalink, $post_id, $leavename ) {
    $post = get_post($post_id);

    if ( $post->post_type == jp_event::POST_TYPE ) {
        $rewritecode = array( '%event_id%' );
        $rewritereplace = array($post->ID);
        $permalink = str_replace($rewritecode, $rewritereplace, $permalink);
        return $permalink;
    }
    return $permalink;
}

How do I make this code work? What am I doing wrong?