I just discovered that the engineers have an access plate to enable reaching the 4 nuts that secure the brake booster. The plate is approximately 3.5 by 5 inches. The plate is a bit larger at the top than the bottom. It's secured by 4 bolts/screws. The locality is behind the booster inside the wiper arm access area. It is sealed with some kind of tar based sealant to avoid leaks into the cabin area. How many of us struggled to get to those nuts? My body still hasn't recovered from the contortions. My swear jar is overflowing from words I didn't even knew that I knew. The aim manual actually show this. I sure hope this helps others.............too late for me. I'll take a picture of it and post it later.   

Which would ya rather have....a sore back, or a Shark full of water? 
It's true that the plate can possibly be removed for better access, but.....it's glued on there pretty well, and getting it sealed back up will be tricky. Might be worth it for a full resto job, but for a normal booster replacement? Hhhmmmmm....maybe, maybe not. With the right tools, getting the nuts off isn't that much trouble, compared to removing/replacing that plate, and taking a chance on having a leak that wasn't there before, imho. Of course, we all know these things never leak anyway, right?

 Ya, after the fiasco we had in Effingham changing the one in the parking lot, I am aware of the back ache. We did not use the plate, did not appear to even be there.

There were extenuating circumstances in that case, Mark. I don't think getting the nuts off/on was the big problem on that one....The threads on the clevis were buggered up, and that dang clip dint wanna go back in the pin. Had it not been for those things, that booster change would have been much more straightforward. It was a pita, tho, right?