The menu says I can have this feature on.. the adverts said so as well. How do I work this bit?
I think it's on by default. There should be an option under Setup>Other. I've got it on but I haven't seen very many limbs fly. It doesn't always happen.
have you tried the "g_saberrealisticcombat 1" cheat? just enter that in the console after you type in "devmapall". Then you'll only have to worry when you don't chop someones limbs off.