Can't enable swapping in mac os x 10.8.3

Can't enable swapping in mac os x 10.8.3

some time ago a disabled swap. I need to enable it now and i was not managed to do it with help of
sudo launchctl load -wF /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist & reboot
my virtual memory properties:
sudo defaults read /Library/Preferences/com.apple.virtualMemory
{
    DisableEncryptedSwap = 0;
    UseEncryptedSwap = 1;
}
and swap usage is
sysctl vm.swapusage
vm.swapusage: total = 64.00M  used = 0.00M  free = 64.00M  (encrypted)
At this very moment i have 4 gb active memory used and 1 gb wired and 2 gb inactive. my mac book pro has 8gb RAM. Activity monitor shows that swap is not used( i mean swap = 0 bytes, page outs = 0 bytes)
Can anybody help me to enable swapping back?