Ok, I know this is a recent feature, but it doesn’t work for me when I try using it in Haiku. My computer has a measly 128 mbs RAM, so using Virtual Memory (or Swap) is a must. When I try to enable Virtual Memory, and close it, it opens up with virtual memory disabled again. Even after restarting, virtual memory still remains disabled. Anyone know whats going on?
Thanks to everyone who helps. 
Is this on a recent revision? If so, please open a ticket at http://dev.haiku-os.org , hopefully the devs will be able to help you.
There needs to be enough free disk space on the boot partition to enable Virtual Memory. The minimum is equal to the size of RAM on the system.
It wasn’t on a recent revision. It was on a slightly older one (which is gone right now, since it was on my old computer which got wiped).