API? Hook? PHP Condition code not working

[Bilderback]

When writing to a php file outside the forum directory (global.php is included),
what are the php equivalents to the template conditionals:
<if condition="$show['member']">
<if condition="$bbuserinfo[field5]">
<if condition="is_member_of($bbuserinfo, array(5,6,9))">

In my portal navigation (level up from /forum),
I am trying to set conditions on the viewing of certain navigation buttons.
Does anyone know why the following do not work?
~trying to limit viewing of this url to members

PHP Code:

<?php if ($vbulletin->userinfo['userid']) { ?>
    <li><a href="forum/mypage.php">My Page</a></li>
<?php } ?>

~trying to limit viewing to admins

PHP Code:

<?php if (is_member_of($vbulletin->userinfo, 6)) { ?>
    <li><a href="admin.php">Admin</a></li>
<?php } ?>

What is the proper way to write vb variables to php files outside the forum directory?
Would I need to write hooks?
Thanks