Yes, I have seen it and I know Wolfang pretty well.

What he did is work out the stock finger clutch of the NMT 2 speed and he did his own design.

You can imagine adding a second finger to the original clutch, and it will basicaly work as a clutch.

I can't show you pics or anything but it wasn't that difficult to mod.

Just a bit curious, but why do you want a clutch type 2 speed ?

DFF