Ive made it!
Using this function instead of the Select, I set the field readonly, set focus on it (a readonly field does not activate the keyboard), wait a while for the focus and set it not read only.
I works!
This is the function:
function hideKeyboard(element) {
element.attr('readonly', 'readonly');
element.focus();
setTimeout(function() {
element.focus();
element.removeAttr('readonly');
}, 100);
}
And this is how I call it:
p_web.Script('hideKeyboard($("#loc__CodigoEnvio"))')
where loc__CodigoEnvio is my entry field id
Hope it helps someone.