I have used a couple of days to try to figure out how to underline the accesskey on a commandbutton but without any luck. It works on <button> elements but not on <a4j:commandButton> nor <h:commandButton> components. I tried with <span> elements and CSS coding, but it does not add any meaning. Many people request this feature but it seems it not possible. Anybody that know if it is possible to have the accesskey underlined?