I have experienced what you have and after understanding a little about the failure, added a couple braces below and above the radio. I was told HD changed the braces in 08 (if my memory is correct) to add more support. I've put on a lot of miles since the new radio with the braces and all is well.
On a side note, the braces also took out a lot of the fairing vibration I had both at idle and cruising. I think the lower brace did the most to help, but don't over look the braces, they need to be inspected and either replaced or repaired to minimize future failures.
The more mods you do to a bike to increase the vibration, the more issues you can have. I have a urethane front mtr mount, the first version of sta-bo bushings in the swing arm and a set of cams, all of which have added some vibration to the bike.
For the lower brace, you need to be careful, not a lot of room between the radio and where this brace goes. I used existing holes in the vertical brackets to mount the braces with the same bolts that the radio uses for mounting.
Let me know if you have any questions.
Brad