PHP

$template->assign_vars(array(
  'USERNAME_FULL' => get_username_string('full', $userrow['user_id'], $userrow['username'], $userrow['user_colour']),
  'USERNAME_COLOUR' => get_username_string('colour', $userrow['user_id'], $userrow['username'], $userrow['user_colour']),
  'USERNAME' => get_username_string('username', $userrow['user_id'], $userrow['username'], $userrow['user_colour']),
  'U_PROFILE' => get_username_string('profile', $userrow['user_id'], $userrow['username'], $userrow['user_colour']))
);

HTML

{USERNAME_FULL}