function addMirrorFunction($mirror, $type, $version, $name = '')
    {
        if (!isset($this->_channelInfo['servers']['mirror'])) {
            $this->_validateError(PEAR_CHANNELFILE_ERROR_MIRROR_NOT_FOUND,
                array('mirror' => $mirror));
            return false;
        }

        $setmirror = false;
        if (isset($this->_channelInfo['servers']['mirror'][0])) {
            foreach ($this->_channelInfo['servers']['mirror'] as $i => $mir) {
                if ($mirror == $mir['attribs']['host']) {
                    $setmirror = &$this->_channelInfo['servers']['mirror'][$i];
                    break;
                }
            }
        } else {
            if ($this->_channelInfo['servers']['mirror']['attribs']['host'] == $mirror) {
                $setmirror = &$this->_channelInfo['servers']['mirror'];
            }
        }

        if (!$setmirror) {
            $this->_validateError(PEAR_CHANNELFILE_ERROR_MIRROR_NOT_FOUND,
                array('mirror' => $mirror));
            return false;
        }

        $set = array('attribs' => array('version' => $version), '_content' => $name);
        if (!isset($setmirror[$type]['function'])) {
            $setmirror[$type]['function'] = $set;
            $this->_isValid = false;
            return true;
        } elseif (!isset($setmirror[$type]['function'][0])) {
            $setmirror[$type]['function'] = array($setmirror[$type]['function']);
        }

        $setmirror[$type]['function'][] = $set;
        $this->_isValid = false;
        return true;
    }