Unfortunately it's still rewriting to email@example.com
Would my original suggestion of changing the hostname to "" and domain name to "sever2.main-domain.com" in the ispconfig Management > Server > Settings > Server Tab work? Would it break anything?
Reason I ask is because I noticed I need to move the hostname to the domain name box when creating new webs using the same domain name, otherwise the entry in local-host-names is incorrect, but that may be a totally different issue.
Thanks for your continued help and support!