I came to this forum today looking for an answer to this question and couldn't find it... so I started trying to figure out the answer myself. Found it...
I'm in the US, so my version of the game might be a little different. The editor is something SI didn't change when they ported the game over to WSM2007 from FM2007. So perhaps some things will remain the same.
Anyway - check your 'my documents' folder for a Sports Interactive folder... inside there you'll find a db folder containing a folder with the same name as your edited database (let's call it 'superteam'). You'll want to move that entire superteam folder to C

Program Files\Sports Interactive\Worldwide Soccer Manager 2007\data\db. There should already be a folder in there called "700" or some such thing. Once done, when you click new game, you'll be given a choice of which database to load.