public function headerText($header, $text, $not = false,
                                array $opts = array())
    {
        if (!isset($this->_search['header'])) {
            $this->_search['header'] = array();
        }
        $this->_search['header'][] = array_filter(array(
            'fuzzy' => !empty($opts['fuzzy']),
            'header' => Horde_String::upper($header),
            'text' => $text,
            'not' => $not
        ));
    }