Posts 2 Posts: query connected — orderby problem

Question

Using Posts 2 Posts plugin I've created 'piece', 'person' and 'collection' custom post types: any piece may be connected to person (with roles 'author', 'conductor' etc) and collection.

Now the relevant code looks like this:

// get all audio pieces connected to current $person:
$audio_ascond = p2p_type( 'pieces_persons' )->get_connected( $person->ID,
      array( 'connected_meta' => array( 'role' => 'conductor' ),
         'media_tag' => 'audio_tag',
         'posts_per_page' => -1 ) );
// get their IDs:
$audio_ascond_IDs = array_map( create_function( '$p', 'return $p->ID;' ),
                                      $audio_ascond->posts );
// get collections for those pieces:
$colls = p2p_type( 'pieces_collections' )->get_connected( $audio_ascond_IDs,
            array( 'orderby' => 'menu_order title', 'posts_per_page' => -1 ) );

So, the problem is that 'orderby' has no any effect. Everything else works great. print_r($colls) looks like ok.

What this could be, please?

Thanks!