I’ve a couple of devices that do have a button … and found out that you really must use the button, pulling the power doesn’t cut it. (some other users have the same experience … and it’s pretty unfortunate for those that have devices mounted in most inaccessible places, but can control PoE power delivered to them).
BTW, found this post explaining how to find button on RB1100AHx2: http://forum.mikrotik.com/t/reset-button-on-rb1100x2ah-nowhere-to-be-found/96839/1 (look also at some of next posts there)