Need help setting "Disposition-Notification-To" to external mailaddress

[Kastenmaier]

Hello

I want to set "Disposition-Notification-To" for mail adresses in a domain of the zcs, to an external mail adress.

Background:
The mails of the users in this account are sent over mta (which works great).
The external recipient of mails get as answer mail adress the mta mail adress (lets say mail.t-online.de).
But if mail notification is enabled, the "Disposition-Notification-To" in Mail header is the zimbra adress (lets say user.zimbra.org).

Is it possible to set "Disposition-Notification-To" to mail.t-online.de?

Thanks for your assistance.

Best regards
Randolf Kastenmaier