All you need is 3 foot long, triple-jointed arms, eyes and lights embedded in your hands, and more patience than anybody I know. There are those on the forum who claim to have gotten to the nuts that hold the trim panel on, but I think they really used a very small trained monkey.
When I had my floor off, I stuck my head and torso up through the place where the driver's feet usually are, and stuck my arm as far is it would go into the recess where those gauges live. I think I maybe touched one or two of the nuts back there.
There is a thread here that talks about removing the panel, complete with pics (taken by the monkey, no doubt) showing where the retaining nuts are. I'll see if I can find it.
Edit - Here are the pics
I didn't take these (not being a trained money

), so I can't comment on them.
Jeff