I have corrected the menu system so tabs are generated by drupal. I don't know how to make a patch, but the menu hook looks like:

function answers_menu($may_cache) {
  $items = array();
  $nid = (int)arg(1);
  global $user;

  if ($may_cache) {
    $items[] = array(
      'path'     => 'quest/list',
      'callback' => 'answers_list',
      'title'    => t('Browse Quests'),
      'access'   => user_access('access content'),
      'type'     => MENU_NORMAL_ITEM);
    $items[] = array(
      'path'     => 'quest/list/ans',
      'callback' => 'answers_list',
      'callback arguments' => array(0),
      'title'    => t('Browse Quests'),
      'type'     => MENU_DEFAULT_LOCAL_TASK);
    $items[] = array(
      'path'     => 'quest/list/uans',
      'callback' => 'answers_list',
      'title'    => t('Unanswered Quests'),
      'access'   => user_access('access content'),
      'type'     => MENU_LOCAL_TASK);
   } 
    
  $items[] = array(
    'path'     => 'admin/settings/answers',
    'callback' => 'drupal_get_form',
    'callback arguments' => array('answers_settings'),
    'title'    => t('Answers settings'),
    'description' => t('Configure Answers service settings'),
    'access'   => user_access('administer content types'),
    'type'     => MENU_NORMAL_ITEM
  );

  return $items;
}

And answers_list() like this:

function answers_list () {
  $ansset = 'active';
  if (arg(2)=='uans') {
  $ansset = '';
  $unanset = 'active';
  $filteranswered = TRUE;
  
  }
  return $o = theme('answers_list', $filteranswered);
}

I would like to make unanswered questions just available to some users, but I don't have time right now to implement this (maybe later).