Here is an example of how
vb does it in announcements.php.
$navbits["$vboptions[forumhome].php"] = $vbphrase['announcements'];
$navbits = construct_navbits($navbits);
eval('$navbar = "' . fetch_template('navbar') . '";');
eval('print_output("' . fetch_template('announcement') . '");');
I'm just not sure of the syntax to do the same in header-inc.php.