public function setVideoClicksClickThrough($url)
    {
        // create cdata
        $cdata = $this->getDomElement()->ownerDocument->createCDATASection($url);

        // create ClickThrough
        $clickThroughDomElement = $this->getVideoClicksDomElement()->getElementsByTagName('ClickThrough')->item(0);
        if (!$clickThroughDomElement) {
            $clickThroughDomElement = $this->getDomElement()->ownerDocument->createElement('ClickThrough');
            $this->getVideoClicksDomElement()->appendChild($clickThroughDomElement);
        }

        // update CData
        if ($clickThroughDomElement->hasChildNodes()) {
            $clickThroughDomElement->replaceChild($cdata, $clickThroughDomElement->firstChild);
        } else { // insert CData
            $clickThroughDomElement->appendChild($cdata);
        }

        return $this;
    }