Q: OS X Server Account customization

Hello community!

I've got a small server that have been setup for years and which I haved upgraded several times.

Since 10.11 and iOS 9, the "OS X Server Account" is available for clients and it is easy to set them up with it.

I've got a little problem with this, because the default smtp-out port is 25. On residential connexions, it is often blocked.

In the logs, I see :

GenericPlugin(servermgr_mail): doCommand request is {

            command = customizeUserProfile;

            defaultProfile =     {

                EmailAccountDescription = "Generated Account";

                EmailAccountType = EmailTypeIMAP;

                EmailDomain = "menzonet.org";

                IncomingMailServerAuthentication = EmailAuthKerberos;

                IncomingMailServerHostName = "myserverfqdn.tld";

                IncomingMailServerPortNumber = 143;

                IncomingMailServerUseSSL = 1;

                OutgoingMailServerAuthentication = EmailAuthKerberos;

                OutgoingMailServerHostName = "myserverfqdn.tld";

                OutgoingMailServerPortNumber = 25;

                OutgoingMailServerUseSSL = 1;

                PayloadDisplayName = "myserverfqdn.tld Mail";

                PayloadType = "com.apple.mail.managed";

            };

            userName = myusername;

        }

Apr  7 11:20:36 myserverfqdn servermgr_mail[388]: GenericPlugin(servermgr_mail): doCommand running customizeUserProfile

I would like to change this so the OutgoingMailServerPortNumber is 587, is it possible?