I bought a Sena SMH10 for my EXO 900-X but the clamp did not fit over the helmet rim. The double sided adhesive foam pad couldn't hold the bracket to the odd shaped helmet. So I decided to modify the helmet rim so I could use the provided clamp and not rely on adhesives.
Removed two Phillip screws holding the left front side together and a smaller screw securing the rim near the left ear. I marked out where I wanted the communicator to go and used a Dremel to cut the rectangle. A razor blade took care of the rest. The expanded foam is easy to move and there's adequate room between the foam and helmet to secure the Sena bracket.
I think it turned out pretty well and I'm satisfied with the results.