Where to specify Exchange server address for autodiscovery?

I have z-push working fine, and am in the process of configuring the auto discovery feature. Everything seems to work fine, except the devices are getting the wrong mail server address. Our users have the email addresses user@domain.com, and our mail server is located at mail.domain.com. The mobile and activesync devices are automatically filling in “domain.com” in the mail server address field of the cleint, instead of “mail.domain.com”, and I can’t seem to find the location for specifying this anywhere.

Where can I specify what should go in the Exchange/Mail server address field?

That was the guide that I had been following. I’m not sure if my implementation was incorrect, but adding the line:

AliasMatch (?i)/Autodiscover/Autodiscover.xml "/usr/share/z-push/autodiscover/autodiscover.php"

to my Apache configuration did not work. Once I created the autodiscover.domain.com DNS entry, then it started working for mobile devices.

The Windows 10 Mail client still does not work, but I think this is caused by a bug as outlined here:
https://forum.kopano.io/topic/570/z-push-autodiscover-on-2-3-7-not-working-as-expected/8

EDIT: The Outlook 2016 client works with z-push autodiscover once I install the Kopano Outlook Extension. All is well!

Thank you!