Using the center column for azimuth motion on the Bogen Tripods (even the older ones) doesn't work well anyway, imho. There is a rubber o-ring that causes sticky motion and the locking system isn't adjustable enough anyway. Most alt-azimuth heads have a built in azimuth motion anyway. If yours doesn't then it wouldn't be that hard to make one from some teflon, laminate, thin plywood and a bit of hardware. Also, there are well made panning adapters made which will provide smooth azimuth motion, you just need to find one without click stops. Hope this helps.
Joplin
Joplin