Go to your local trophy shop and have them make a plaque you can attach with button head cap screws.
I'm guessing you already had this done. I would really like to see this; so post a picture.
I personally just cut the original handle bars so all was left was the 2 inch piece left between the two mounts. From that you can mount a GPS or whatever since most motorcycle mounts require a handle bar or something. TOB has pictures of my GPS mounted there.