/**
  * Add a CDATA node to this element.
  * @param string
  * @return boolean
  */
 function setCDATA($text)
 {
   if(! ($this->___t == ISTER_XML_TAG) || ($this->___t == ISTER_XML_DOCUMENT) )
     return $this->log('cannot add CDATA here', E_USER_WARNING, 'setCDATA');
   $cdata = new IsterXmlNode(ISTER_XML_CDATA, $this->___l + 1, $text);
   $this->___c      =  array($cdata->toSimpleXML());
   $this->ref->___c =& $this->___c;
   return true;
 }