UPS-XML problems with Mexico

I'm getting no estimate or option. It's enabled in the admin, I even get a fieldset and legend for it at the "checkout - step one", but there's nothing there. I've enabled the log, and I get a successful response. It dies somewhere after that with no output whatsoever. Is it a 1.5.1 compatibility issue?

after a var dump it's showing that the quote=>methods array is empty even though I've specified worldwide expedited in the admin (and it's in my database)

found the problem. My country of origin was mexico. In the includes/languages/english/modules/shipping/upsxml.php file the mexico origin defines all left out the "worldwide " from their definition, so:

    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_07', 'UPS Express');
    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_08', 'UPS Expedited');
    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_54', 'UPS Express Plus');

Becomes:

    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_07', 'UPS Worldwide Express');
    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_08', 'UPS Worldwide Expedited');
    define('MODULE_SHIPPING_UPSXML_SERVICE_CODE_MEXICO_ORIGIN_54', 'UPS Worldwide Express Plus');

and problem solved.