Mine has a mounting bracket as well, but that doesn't help one bit if there's no place on the bike where it will fit!
I really have tried every reasonable location, and it just doesn't fit.

I tried to mount it vertically from my left chain stay, but I found I hit it with my foot constantly.

The right chain stay has a chain inconveniently placed in the way...

The seat stays are too cluttered to have any room left for it.

The lock itself doesn't fit inside the main triangle unless mounted out in front of the seat tube, but that requires the bottle cage to be removed.

There's not enough space to have it on top of the top tube, and my private parts wouldn't be very comfortable with that location either.

Mounting it on the fork is out of the question, for obvious reasons...

Hanging it around the seat tube and the seat stays doesn't work either, as the lock is too wide. My legs would chafe on it all the time, if I even managed to pedal.