At this moment (firmware 7.00) it's not possible to assign the outcome of a choice to a button. This can only be done through custom settings of which there are only seven.
What I would like to be able to do is, for instance, assigning AF-C to one button and AF-S, Manual Focus to others. Same with Subject Detection, give humans, animals and birds each their own button. There are too many of these settings to capture under the 7 custom settings. For me it would be like a natural extension of the custom setting system. The custom settings are great for a general setting, 'micro adjustments' can be assigned to buttons. In the current setup you need to press a button and then make a choice, which is cumbersome. You want just one press of a button and be done.
