ok so,
1/ First off, get a piece of cardboard and put the strut brace on it, mark the position of the holes on the cardboard to measure the bend you are putting on it.
2/ Put it in the vice in the position shown in my diagram

MAKE SURE IT IS STRAIGHT..
3/ Apply pressure where shown.
4/ When you feel it ever so slightly bend, take it off and compare it to the position on the cardboard.
5/ Do the same on the other side. You will be able to see that the holes will come slightly closer together on the carboard.
Bit of a bitch of a job to do but it's definetely worth it, really tightens up the bottom end.
scott