Variables disappear in template

[mts7]

I have a custom template that worked with vB 3, but now with vB 4, the variables are not being displayed. I noticed that they were still in the old syntax ($variable), so I put them into the new syntax ({vb:var variable}). With the old syntax, I saw the text of the variable name, but not the contents. With the new syntax, I see nothing.

I didn't write this template, but I am now the one to maintain it. What needs to happen between assigning the variable in profile.php and $templater->register('HTML', $page_templater->render());?

PHP Code:

if ($_REQUEST['do'] == 'mycustomaction')
{
    $custom_variable = '<p>This is my custom variable.</p>';
    construct_usercp_nav('custom');
    $navbits['']  = "My Custom Page";
    $page_templater = vB_Template::create('customaction');
}

if (!empty($page_templater))
{
    // make navbar
    $navbits = construct_navbits($navbits);
    $navbar = render_navbar_template($navbits);

    ($hook = vBulletinHook::fetch_hook('profile_complete')) ? eval($hook) : false;

    // add any extra clientscripts
    $clientscripts = (isset($clientscripts_template) ? $clientscripts_template->render() : '');

    if (!$vbulletin->options['storecssasfile'])
    {
        $includecss = implode(',', $includecss);
    }

    // shell template
    $templater = vB_Template::create($shelltemplatename);
    $templater->register_page_templates();
    $templater->register('includecss', $includecss);
    $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('clientscripts', $clientscripts);
    print_output($templater->render());
} 


Any help and insight is greatly appreciated. :-D

--------------- Added [DATE]1305760928[/DATE] at [TIME]1305760928[/TIME] ---------------

It took me a bit of time, but the solution was to make the first part like this.

PHP Code:

if ($_REQUEST['do'] == 'mycustomaction') 
{ 
    $custom_variable = '<p>This is my custom variable.</p>'; 
    construct_usercp_nav('custom'); 
    $navbits['']  = "My Custom Page"; 
    $page_templater = vB_Template::create('customaction'); 
    $page_templater->register('custom_variable', $custom_variable);
} 


I tried the register in the lower part, before the render, then realized that $page_templater is what needed the variable registration. I hope this helps someone.