Gitzo 3542L question about snow feet

I noticed that the 3542L comes with three plastic snow disks and three nuts. When I pulled the rubber feet off the legs, there were spikes, but no threads onto which to screw the nuts to hold the plastic feet. Can someone explain how to attach the snow feet?

I'd say to unscrew the spike, place the insert into the snow shoe, thread the spike through the insert up into the leg.

I believe the spikes simply screw out - I think there is a tool included for doing this.