Code:
$navbar = render_navbar_template($navbits);
$templater = vB_Template::create('USERCP_SHELL');
$templater->register_page_templates();
$templater->register('cpnav', $cpnav);
$templater->register('HTML', $page_templater->render());
$templater->register('navbar', $navbar);
$templater->register('navclass', $navclass);
$templater->register('onload', $onload);
$templater->register('pagetitle', $pagetitle);
$templater->register('template_hook', $template_hook);
$templater->register('includecss', $includecss);
$templater->register('includeiecss', $includeiecss);
print_output($templater->render());