Like Mechie3, I ground off the remainder of the boss, and part of the side so that the bracket fit flush. You can see some of it in this video:

https://plus.google.com/u/0/b/107272...88473870379365

One thing to note is that when I went to mount the shock bracket (after I made that video), I found I couldn't use the captured nut bracket supplied by FFR. My solution was to buy some good nuts and washers. This necessitated similar grinding on the bottom to achieve a nearly flush, and therefore snug, fit. Then I added loctite just because...