Try something more like this:
PHP Code:
$templater = vB_Template::create('tmplt_simpleWord');
$templateValues = $templater->render();
vB_Template::preRegister('header', array('templateValues' => $templateValues));
And then use {vb:raw templateValues} in the template.
Did you look in the file I told you to? You'll see the hook location parse_templates right above where the templates are rendered. Why not try that hook location?