Was browsing for more info on the elusive SA-4/3M8M3, instead I found these:

http://www.fortifikace.net/pov_pvos_skupina_vega.html
http://www.fortifikace.net/pov_pvos_skupina_vega_rapotice.html

Also, I'd be very interested in any information you could provide about the SA-4, such as the reference sites you used while creating the system. I've been unsuccessful so far in finding any truly in-depth information regarding the SA-4, or the 3M8M3.