I've got your standard low tone Fiaam horn in the right pod. Now this is on my Std that I added pods to. I just took off the stock horn and replaced it with the Fiaam. I think the horn came with 2 steel straps for mounting. The horn shoots out the pod opening.
I'm not sure if the same mounting bolt exists on an I/S, and I can't find on HDL's fiche the horn on a Std to get a look at it.
How about using a "P" clamp on the area of the crash bar that is hidden by the pod as a mounting point?

