All pages but one in https

I use Ubercart with an ATOS/SIP payment gateway.

This gateway sends auto-response after payment that demand a target url to not be HTTPS.

the hook_menu defines the url as cart/atos/autoresponse and a page callback that begins by :

function uc_atos_autoresponse() {
  if (!isset($_POST['DATA'])) {
    watchdog('uc_atos', 'Autoresponse attempted without any POST data.', array(), WATCHDOG_WARNING);
    return;
  }

  $response = _uc_atos_parse_response($_POST['DATA']);
...

In secure page, I set every page secure but this URL.

Do I really need this module to achieve that?
Could I redirect all pages in Apache to ssl pages but this one instead?

Thanks for help