Probably best to give Axiom a call or email. They used to have diagrams on the web site indicating where you should screw the FMB to the back of each speaker model, but I guess they took the pics down after shipping the mounting bolt for a while.

http://www.axiomaudio.com/contact.html

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8