are you planning on mounting them behind the bumper inserts? if so, the easiest thing to do is this. take out the inserts. make yourself a little bracket, rectangular in shape. screw the bracket to the top portion of the bumper cover, with the bracket on the topside of the bumper. the insert will cover the screw. think of it like this: bracket, bumper, insert (from top most down). the bracket will stick out from the rear of the bumper, mount the foglamp to the bracket.
very simple. i have not looked at the bumper itself to be 100% sure this will work, but it should. i will look at it later today to be 100%.
also, if you need pics of what i am trying to say, i will try to make some for you.