I think I've done it by changing the theme's pagination.tpl to look like this (the last lines generating the form):
<form action="{if !is_array($requestNb)}{$requestNb}{else}{$requestNb.requestUrl}{/if}" class="pagination">
{l s='items:'}
{foreach from=$nArray item=nValue}
{$nValue|escape:'htmlall':'UTF-8'}
{/foreach}
</form>