$new_addr = '';
foreach ($_GET as $key => $value) {
if ($key == 'pkNouvelle') {
$key = ltrim($key, 'pk');
$new_addr .= $key . '_';
}
$new_addr .= $value . '_';
}
$new_addr = rtrim($new_addr, '_') . '.html';
header('Location: [url]http://www.example.com/[/url]' . $new_addr . ')';
Edit: vBulletin messes up the "header()" text. I'm not going to try to fix it.