I know that by typing a command:
into the terminal window you can switch back to compiz, but this only works till the next logout/reboot. I want to switch for good.
In Natty Narwhal I can't see any options in Preferences/Appearance to do that.
There must be a configuration file somewhere, I guess?
I checked the value you give and it was already set to compiz. However, only after using 'replace' command I get the required functionality like workspace edge.