I took a short thin bolt and drilled a hole in the PVC and threaded the bolt through the PVC, added 2 flat washers, went through the already precut hole in the clamp, and then added a lock nut. Tightened it down, and our good to go.
I ride a lot due to the fact my club is quite but spread out and this allows me to be able to attach it anywhere.
I also made my father one for him to use when he's smoking one, he isn't a golfer so it works in other contexts as well.
EDIT: the lock nut is actually in the PVC pipe and the head of the bolt is against the clamp.