Then it will require to add new variable via the code. For example, {author_id}. Then add the processing in modules/boonex/posts/classes/BxPostsMenuView.php after the line like:

parent::__construct($aObject, $oTemplate);

need to add the new one like:

$this->addMarkers(array(

            'author_id' => $this->_aContentInfo[$CNF['FIELD_AUTHOR']]

        ));