You can set the timer mode so that it will fire three shots. So when you want to shoot a bracket sequence set the dial to timer mode, hit the shutter release once and it will click three times. You just have to remember to spin the dial to a different drive mode after that. And there is a slight 2s delay because I think 2s is the shortest timer waiting time. There is also .5 sec between shots.
To turn off bracketing you just hold down the BKT button and spin the command dial to 0F.
Or what I have done is set one of the User custom modes (U1 in my case) as my HDR mode. So I have that mode set to bracket. In order to shoot HDR I spin the dial to U1 and the drive dial to timer mode. Then when I don't want to bracket any more I switch back to Aperture priority and turn the drive dial to Q or S or whichever.