youcantdothathere, i suspect you are hooking it up differently than i have, as i tried my theory out and it will not even work, cant even get far enough to test. all of the button conductors tied to one, that does not work, my bad.
sorry for leading you astray dema, but if you really want the function i may be able to figure a really complex system for doing it. but i would just hold the buttons like you would have to on a real controller.
also i am testing on a dc, as i do not have a xb, but that should not matter.