Custom postfix config / always_bcc

I need to log all incoming and outgoing messages. Postfix gives you a way to do this by setting always_bcc in the config file. (I want to push a copy of every message to a go/rethinkdb server for storage/API)… From what I’ve read you can’t do ANY customization with mail-in-a-box. Is this 100% true? If I go in to the server and tweak postfix settings will they get overwritten? Or should I fork the codebase and make the changes there?

Thanks.

Jack

Postfix settings won’t get overwritten.