public function replyToCommentEntry($commentEntry, $commentText)
    {
        $newComment = $this->newCommentEntry();
        $newComment->content = $this->newContent()->setText($commentText);
        $commentId = $commentEntry->getId();
        $commentIdArray = explode(':', $commentId);

        // create a new link element
        $inReplyToLinkHref = self::VIDEO_URI . '/' . $commentIdArray[3] .
            '/comments/' . $commentIdArray[5];
        $inReplyToLink = $this->newLink($inReplyToLinkHref,
            self::IN_REPLY_TO_SCHEME, $type="application/atom+xml");
        $links = $newComment->getLink();
        $links[] = $inReplyToLink;
        $newComment->setLink($links);
        $commentFeedPostUrl = self::VIDEO_URI . '/' . $commentIdArray[3] .
            '/comments';
        return $this->insertEntry($newComment,
            $commentFeedPostUrl, 'Zend_Gdata_YouTube_CommentEntry');
    }