Hi Alberto,
>is there a version of DisclaimIt for office 365?
because MS does not allow to deploy 3rd party software (like DisclaimIt) on their Exchange servers in their cloud, DisclaimIt can't be used directly in the Office 365 environment.
There's one technically possible solution: Configure Office 365 to forward all Internet-going messages to your own on-premise Exchange server with DisclaimIt installed, where the signatures & disclaimers are added, before the messages are then sent to Internet recipients. While this solution will work (I know of at least one customer who implemented this scenario), if it's worth the effort may be doubted...
-Franz