These switches are press-fitted into the streering wheel. Each switch assembly has two "posts" angled directly into the steering wheel cavity.
I don't have pictures of their removal, but the best way to do this is:
1) Wait for the steering wheel and the interior to warm up. These buttons are easier to remove when they're warm.
2) Find a (clean) popsicle stick. Yes, that's not a misprint. A screwdriver will scratch the plastic, or, worse, damage the circuit board inside the switch assembly.
3) Carefully push the end of the popsicle stick into the opening at the back of the side of the assembly and angle it so that the end that you insert is facing you. You should be able to get about an inch into the assembly. Do this directly in the middle of the assembly so that you don't damage the circuit board inside the switch assembly.
4) Carefully push the popsicle stick and switch assembly directly toward you. When you get about 1/4" of the switch out, you can pull it out the rest of the way with your fingers.
5) Depress the tab on the electrical connector to disconnect it.