Annie,
I feel for you. I have the same lock with the alleged "EZ Lock". Someone at the Kryptonite marketing department definitely needs to be fired for naming it so. I have had the exact same struggles and i finally threw the stupid thing away. I even tried putting the Dremel to it and lots of lube in hopes of easing the lock into the bracket. No such luck.
Anyway, around the same time i got a pannier from MEC. I got this one ( http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442619352&FOLDER%3C%3Efolder_id=2534374302693397&bmUID=1268092418954 )
It has a hidden compartment in the back which hides the backpack straps. The lock just happens to fit in there. Although it was never intended to be a storage pocket, it is does the job, nobody is complaining, and i'm happy
So that was my solution. I have seen others put their lock in their rear rack, but my lock doesn't fit through the rack. My lock is too thick.
Short of carrying it in a bag, or dare i say sticking it down your pants, AnnieD, like i've seen some guys do, i'm not sure what solution there is other then finding a bracket that works.
If you find a suitable bracket solution, please keep us posted. There are many of us struggling with where to keep a 6lbs piece of U-shaped iron we call a lock