Thanks. The mirror assembly is off the car. I replaced it with an entirely new mirror assembly. Now that I can play with the one that won't fold and if I screw up, I won't feel so bad.
If the spring is as tough as you say to get it back in place, I'm guessing that I'll have to mount the mirror to a 2 x 6 or something and then put the 2 x into a bench vice. It sounds like I'm going to need two hands to work the spring so holding it my lap or on a bench with one hand probably isn't very likely.