custom reject message for reject_sender_login_mismatch

[Stefan Bauer]

Hi,

using

smtpd_sender_restrictions = reject_authenticated_sender_login_mismatch
smtpd_sender_login_maps = hash:/etc/postfix/login_maps

rejects user with invalid mail from domain with

<a@b.c>: Sender address rejected: not owned by user abc; from=<a@b.c>
to=<u...@remote.tld> proto=ESMTP helo=<[192.168.0.173]>

How can i customize this reject message?

Thank you.

Stefan