Modern Buddy

I ordered a head light visor that fits the P. So anyone know how to put it on a Stella?

Problem is the visor has a small turned up lip along its outside curve, but no bead or lip on the head piece its smooth...

Curious, the ones I just looked at seem to have a small 'flange' that looks to me that it simply goes behind the head light bezel and is held in place by that.
I'd suggest you take this question over to Modern Vespa in the 'Not-So-Modern' page, there's lots of 'P' riders there....
(Post a pic as well, that'll help.)