So yeah, this is the flexy i made from my snapped Magray Brake.
First off have a hold drilled in your deck for the bolt, i used a 10mm.
Secondly bend the snapped part of the brake in a vice or with a hammer or however. Making sure the Magray 'M' cutout is going to go UNDER/INSIDE the deck.
Then put the bolt through the cut out like so -
add the nut(s) to the bolt and tighten them down. I used 2 nuts for extra security as they are not nylock nuts, but you can also add locktite.
Put the spanner in the deck on the nuts and hold it in place and the socket on the bolt head and torque them up until its tight. it should be tight enough so that the brake doesn't moved side to side.
view from back -
Wheel on -
you can also file down the end of it where it is snapped for a smooth finish, but i need a new file.
Hope this helped
i probs went to to to much detail but oh well :L