World spawn won't change

I am making a minecraft map in the new 1.7.2 version but the world spawn won't change with /setworldspawn.

I did /setworldspawn on the location I wanted, then I did /kill and I still spawned at the own spawn location ( ).

I thought this was a bug because it also didn't work in the 1.7.2 server .exe.

If this isn't a bug, could you please explain how to change the world spawn point?