Just pull straight up on the knob with all your might. The knob will pop off and the wires taht hook onto the button will pull off when it comes up. There is nothing actually holding the knob on other than friction, so don't worry about breaking anything. this is actually much easier than damaging the top f the knob by trying to use a scredriver to pry it off from teh top down.

Once you get the knob off just push a screwdriver up the hole from the bottom of the knob and push the button + gear map cover plate (they are two different items) out. Once you have this done remount teh knob with the button or plate on, and lead teh wires through the top. This can be annoying since there isn't much slack in teh wires, but be patient and it will work. Connect the button, but it down in place, and push the cover down into place on the top (it slips in on teh perimeter, sliding under a lip in the rubber knob).

Good luck,
Rick