[Plugin: Posts 2 Posts] Querying connections by their fields ?

Thank you, scribu, for the work! Now, following my stackexchange question i run into a problem.

I’ve registered this connection:

p2p_register_connection_type( array(
    'id' => 'pieces_persons',
    'from' => 'piece',
    'to' => 'person',

    'fields' => array(
      'role' => array(
        'title' => 'Role',
        'values' => array( 'conductor', 'composer', 'soloist' )
      )
    )
  ) );

I’ve created a piece, added two persons: one conductor and one composer. And I want to get only conductor for current post:

$conductor = p2p_type( 'pieces_persons' )->get_connected( get_queried_object_id(), array(
    'connected_meta' => array( 'role' => 'conductor' )
  ) );
  echo count( $conductor->posts );

But this echoes 2 — i get both persons.

Please, what’s wrong?

Thanks!