I had the same problem, ended up Mcguyvering mine.
The two bottom bolts can be knocked out, I then drilled appropriate size holes in the rubber then welded two bolts to the top plate to run down through the rubber and out through the frame mount. There are little nubs on the to plate where bolts can be welded..
I used flat washers and a nut on each bolt but not so tight as to overly compress the rubber the added lock nuts to hold everything in place.
At least 15,000 miles on this set up so far without issue
John .
