[calorie]

What do you mean by "use vBulletin code in a nav?" If you mean a plugin, then no, that code you posted would need to be PHPized, i.e., this:

<if condition="$show[member]">
	<td class="vbseo_vbmenu_control"><a href="usercp.php$session[sessionurl_q]">$vbphrase[user_cp]</a></td>
</if>

Becomes something like this:

if ($show['member'])
{
	echo '<td class="vbseo_vbmenu_control"><a href="usercp.php' . $vbulletin->session->vars['sessionurl_q'] . '">' . $vbphrase[user_cp] . '</a></td>';
}

Depending on what you are wanting to do, etcetera.