Fiddling around with yet another Minecraft server admin console means I get to find new ways of messing things up. Not that anyone other than I have spent any time on the server yet, but I found a way to delete the entire world through trying to add a whitelist and then restart the server. Apparently restart means restart the whole world with a different world.
So there goes a bunch of hours. Ah well, it rained there too much anyway.
To answer your question jr0n, it looks you can 'toggle' between creative and survival... all it appears to take is a quick server restart....