Add it after the post count in postbit_legacy template.
Or instead of modifying templates, simply create a new plugin at hook location postbit_display_complete and add the following:
Code:
if ($post['fieldX']) {
$template_hook['postbit_userinfo_right_after_posts'] .= "<dt>PHRASE TO DISPLAY</dt> <dd>" . $post['fieldX'] . "</dd>";
}
Adding a plugin is better than modifying templates because every time you upgrade your forum, you will have to modify the templates once again. Plugins can be easily enabled and disabled.