I did this in my Jeep. The trick is finding the right switch to put behind the button. It has to be able to handle the load, be the right size, and have the right travel (key part) to make it work. What I did, and highly recommend, is to get a bank of switches to mod. This way if you feel the project isn't going well, you can ditch without damage.
This should be a link to the switch bank
I'd share pics, but the thread above pretty much covers it all. Pretty much the same from the WK to WK2 with regard to the switch bank.