Okay, It can be done. But you will need the Vespa headlight rim, not one of the stick on ones, an adapter to plug it into the harness, and you will need to drill two holes, and make one slot, in your existing headset.
I bought a chrome front handlebar cover, because it was cheap and I suspected I would be cutting into it, and I did.
The light does look good, and illuminates better. I'm not sure yet how it will do long term, but am willing to find out. I will post photos eventually.