Horn earth

[Codshead]

I am fitting the original steering wheel back on the car. The one I have taken off has a different earth arrangement, where the earth wire is trapped between the steering wheel flange and the boss at one of the six allen bolts, but there is no way to do this on the original set-up because the wheel slips over the boss and not onto it. Where does the earth wire 'earth out'. Tks for your help.