How to replace FST Driver

UPDATE ... Success! I called B&W and they said the rubber surround might be sticking to the front of the speaker because of age. So, SWMBO suggestee that I use the eraser end of a pencil to push from the back and exert a little pressure. Bingo! The driver came out and I've ordered new midrange drivers for both speakers. A pencil eraser ... go figure. BTW, tech support at B&W is very helpful and knowledgeable.

I did. However, the manual doesn't show what tools, if any, are needed. For example, when I loosen and remove the large, silver screw cover (which is supposed to hold the midrange rod in place), everything remains tight and the driver stays in place. It looks like there may be a special, hexagonal screwdriver necessary to loosen the rod, but I don't know where to get one. Also, the is a circular, brass piece with a rubber gasket that does not appear to be easily removable.