I have had phenomenally good experiences with the gang at Madisound. So, if you can't get PMC to respond, those guys at Madisound are going to do their best to get you moving in the right direction.
Just another wrinkle. Sometimes companies make a driver for a speaker at one point in time, but make changes to the design over the years. You go back to purchase a replacement, and their could have been changes you didn't know about. This is why its unfortunate that PMC isn't speaking up -- they would be on top of developments.
Nonetheless, I wish you good luck as this is very important to your monitoring chain... Now you see why many of us have stockpiles of drivers hidden away.
Best,
Garrett