OK, sorry for the delay, been a hectic day.
The wheel is attached onto a slotted sleeve. On the shaft is a pin that goes through and sticks out of the sides of the shaft. (Mine needs to be pushed through just a little.
The pin goes between two of the slots so it does not slip.
Do you have your wheel or what? The wheel is curved, but could probably be made. Transparent paints are then used to color in the wedges.
You can see where I had to glue the wheel back onto the retainer sleeve.
Hope this helps you (or anyone) out.