Driver Window Power Switch wont work

I have a 94 Buick Regal 3800 2 door and I am trying to remove my power window motor (driver side) but its "riveted" to the door. How do I access those rivets, are they in fact rivets, as you cannot get behind the door skin to get to the back of the rivets?

Do I have to drill the rivets out? What is mounting the power window motor (regulator) to the door?

Thanks,
Syn