This is a shot of the parts that stack up to build the rear hub assembly. These parts fit into the aluminum upright.
The knock off hubs are splined to fit over the axle shaft, on the end of the axle is a nut that you have to remove. You will find a hole in the side off the knock off hub to access a cotter pin that goes through the axle and nut.
This hole is for installation and removal of the cotter pin. Not unlike the front hub of a car.
Un-screw the nut and the hub should slide off and out of the aluminum upright.
I hope this is the answer you are looking for.