add_post_meta displays in admin edit area

Just add custom-field support to your custom post;

register_post_type( 'YourPosts',
        array(
            'labels' => array(
                'name' => __( 'YourPosts' ),
                'singular_name' => __( 'YourPost' )
            ),
        'public' => true,
        'has_archive' => true,
        'supports' => array(
        'title',
        'editor',
        'custom-fields',
        )
        )
    );