this solved my problem, thank you (before I get ban )Indeed, this command won't edit the main.cf of Postfix, but instead the zmconfigd.cf of Zimbra. And there are some rewrite rules, which overwrites the Postfix main.cf at each mta reload.
You can edit the zmconfigd.cf manually. Look for the "SECTION mta DEPENDS amavis", there are several POSTCONF rules. Find the corresponding entries, as I wrote above, and change them for your need. Maybe I had a slight mistake with the zmlocalconfig commands, but edit manually should do the trick.
Of course, my fault:
zmlocalconfig -e postfix_smtp_sasl_password_maps=hash:/opt/zimbra/conf/relay_password
zmlocalconfig -e postfix_smtp_sasl_auth_enable=yes
zmlocalconfig -e postfix_smtp_cname_overrides_servername=no
zmlocalconfig -e postfix_smtp_use_tls=yes
zmlocalconfig -e postfix_smtp_sasl_security_options=noanonymous // Depending on your requirement
The keys have a preceding postfix_ not a preceding postconf_ if you you use the zmlocalconfig.