mod_rewrite, problema

[osvi]

  GNU nano 1.3.7             File: .htaccess                                    

RewriteEngine On
RewriteRule ^xx/([^/]+).html xx.php?id=$1 [L]

  GNU nano 1.3.7              File: xx.php                                      

<?php
echo "aaa" . $_GET[id] . "bbb";
?>

xx.php?id=9 restituisce aaa9bbb [ok]
mentre
xx/9.html restituisce aaabbb

[osvi]