Funny, I just had to do something similar today. To control permissions in a specific world, you have to add it to a group and then tack on the name of the world at the end. You could try adding a negative permission like this, for example the "default" group on your "creative" world:
/pex group default add -factions.* creative
I used this to add worldedit permissions only to my creative world, not my factions one.
You can also just disable the claiming if you want players to still be able to use the rest of factions on a world by going to:
Server/mstore/factions_mconf/instance.json
Go down to this section to control what happens in specific worlds with factions:
"worldsNoClaiming": [
"arena",
"creative",
"world_the_end" ],
"worldsNoPowerLoss": [
"arena"
],
"worldsIgnorePvP": [],
Hope that helps.
Misty
CloudKidZ
