You need a plugin to get the thread id, I believe. Something like (at vbcsm_article_populate_end):
PHP Code:
$record = vB::$vbulletin->db->query_first("SELECT a.threadid
FROM " . TABLE_PREFIX . "cms_article AS a
JOIN " . TABLE_PREFIX . "cms_node ON(cms_node.contentid = a.contentid)
WHERE nodeid = " . $this->getNodeId());
$view->threadid = $record['threadid'];
Now you can use the threadid to make a link in the template.