Martial, I'm afraid I've deleted the download that contained my trial version of Creator, and I don't remember whether that included a key or not. If you don't get an answer from Bentley support in the next day or so, all I can suggest is to try their sales contact page instead:

https://info.e-onsoftware.com/sales-support

Tell them you're interested in buying and have the trial version but it's not working. Ask them if you need a key. They are salesmen so with any luck they will give the support department a hard time until they answer you!