After much forum browsing and question asking, I have gotten the Crystalyte Cruise Control to work with other controllers. I claim absolutely no credit for any of what I have found, ALL credit goes to forum members rkosiorek and methods; all I did was get it to work. I decided to post it because of the number of people I still see asking, and I haven't really found anyone who has actually posted about wiring it to another controller.
After help from rkosiorek, I drew up with this diagram:
I matched that knowledge with the pinouts of the throttle control of my EBikeKit, and came up with this:
It's hard to tell, but I spliced the +5V, GND, and THROTTLE wires in two, and added connectors to both ends. This was to allow the cruise control to be plugged between the throttle and controller without actually modifying the plugs on the throttle or the controller. Notice that the orange wire, BRAKE, is NOT connected, and doesn't have to be unless you want to use it. Cruise control can be turned on and off via the "cruise" button.