Hello!
I have this switch installed and I think I messed up the wiring.
https://www.10pollici.com/en/homepage/classic-vespa/frame/wirings/light-switch-sip-conversion-vespa-50-90-125-et3-primavera-vna-vba-ts-rally-for-electronic-ignitions-with-control-button-for-sip-speedometer.2.1.71.gp.10044.uw
So now it seems the speedo button is always on, the speedo button became the horn and no high beam.