Pop your cabochon out and admire it.
Print out the pieces of the jewelry setting and charging base. I had the best luck printing the pieces one at a time.
This file fits a cabochon that's 22mm tall. You may need to edit the files to make the setting taller or shorter to fit your necklace. You can edit them on Tinkercad here.
Or, if you don't have a 3d printer you can order the setting from Shapeways here.
Place the pendant inside the back ring and place the front ring on top. Be sure it fits snugly, but can be twisted left and right so the tilt switch can be activated and the necklace turned on and off while it's being worn.
Glue the front ring to the back ring, being careful not to get any glue on the resin pendant (or it won't turn in the setting).
Add a necklace chain and clasp to finish it off.