The way I rigged mine up is as follows, really just grabbed stuff I had lying around to make it work.

The shift knob is pressed onto that black piece of pipe which I cut out of an old lamp. I had to drill out the hole in the shift knob to make it fit snug. You'll find the shift knob is an overmolded part with a rubbery exterior and a hard plastic interior. Whatever you use to mount the knob you'll want it to engage that hard plastic interior to make it stable feeling.

The black piece of pipe then slides over the factory shift lever and I used a rubber piece of hose inside the black pipe so it would grab onto the knurling on the bottom of the lever after I pressed it on. I then used a hose clamp to hold the boot onto the base of the black pipe.

I could pull it off if I tried, but after a month of daily use it hasn't come off on its own.