I doubt the star part but I'm glad to help.
Sorry, the stick I did with the thumb wheel on it was for a customer and I never took any pictures. Once you get the idea though, it really is not very difficult.
You can actually do this without any soldering. Open up the base of the stick (hint: there are screws under the rubber feet) and remove the three wires leading to the throttle pot. Then remove the throttle pot which you'll be using. Find three wires of similar gauge and fish them up through to stem that leads up into the handle. You can then cut the connectors off that plugged into the throttle pot and as long as you cut them back far enough, you can strip the insulation off and reuse them once you relocate the pot. Connect the wires that you originally connected to the pot to your new wires and you will have the wiring part done. What you're basically doing is adding an extension to the pot wires as they will be too short to run up into the handle far enough. All you're really doing is relocating the throttle to where your thumb button is now.
I recommend you use some epoxy putty to mount the pot into the thumb button socket once you remove the thumb button. I use
QuikPlastik but any kind of epoxy putty should work. Make a donut of putty and set it around the edge of the pot and mash it into place. Once the putty hardens, it will form a very nice and stable mount. Before the putty dries, you can use a knife and trim off the putty that squeezes through and smooth it out nicely. Once dry, you can use some flat black paint and paint around where the shaft of the pot sticks out and it will look very professional.
As for what to do with the thumb button, that's your call. You could just cut the wires off and do without the button altogether. Or you could find some sort of button and mount it somewhere on your stick if you want to keep it. That's all up to you. If there is room, you could just leave the button connected and stuff it away somewhere inside the stick. That's a pretty lame way to do it but if you're really lazy that would work.
If you haven't already, you can look through all the photos I have at my web site (see my signature). I have a number of pictures of the internals of these sticks. Once you open your stick up though you should be able to figure out what you need to do.
Wish you luck. Let me know if you have any further questions and I'll do my best to help.
