Guys from http://jqueryvalidation.org/ just released version 1.13.1. Checking on their website i see this on the changelog:
CORE: * Ignore readonly as well as disabl
Thank you for you suggestion Panoptik, adding readonly on focusin, and then removing it on focusout was the cleanest way, million thanks! I answer myself in case anyone has the same problem. Hope it helps.
$(document).on("focusin", "#someid", function() {
$(this).prop('readonly', true);
});
$(document).on("focusout", "#someid", function() {
$(this).prop('readonly', false);
});