If you have access to a milling machine, the easiest way to attach to the output hub of the FP KoP gearbox is to mill an octagon-shaped aluminum plug that fits between the plastic flanges. Then just wrap a hose clamp around it, and you're done. You can either broach the aluminum plug for a live axle, or drill a hole pattern into it for dead axle applications (such as if this octagon shaped aluminum plug was bolted directly to your drum).
Here's a photo from the construction of our 2008 robot, which used this octagon aluminum plug. You can click through to the full resolution photo to see it in better detail.
