protected function createFreshKolabPart($content)
{
$part = new Horde_Mime_Part();
$part->setCharset('utf-8');
$part->setDisposition('inline');
$part->setDispositionParameter('x-kolab-type', 'xml');
$part->setName('kolab.xml');
$part->setType(Horde_Kolab_Storage_Object_MimeType::getMimeTypeFromObjectType($this->getType()));
$part->setContents($content, array('encoding' => 'quoted-printable'));
return $part;
}