Please allow the Envelope From address to be changed in the GUI. Currently it can only be changed by modifying the smtpFilters.script file manually. For instance... set (mailFrom, "%MAILFROMLOCALPART%@realdomain.com");

Many companies use .local or other private domains internally and don't what that shown to the outside world. Allowing that to be changed in the GUI would make life a lot easier for many administrators.