Change default Format of Meeting Request Message

[Hatrix]

Hello,

my Client asked me to change the default meeting request email message.

right now it is send like:

==== SNAP ====
subject: xxx
Organizer: xxx

Location: xxx
Time: Starttime - Endtime Timezone

Invitees: xxx
==== SNAP ====

my client would like to have:

==== SNAP ====
Subject: xxx
Organizer: xxx

Location: xxx
Starttime: Starttime
Endtime: Endtime
Timezone: Timezone

Invitees: xxx
==== SNAP ====

i found out that this Message is not build via a template but hardcoded in:
"jetty/webapps/zimbra/js/zimbraMail/calendar/model/ZmAppt.js"

so, what is the correct way to change this? I suppose the typical headaches apply when pathing just the source (upgrade problems, patching again, forget to patch, etc.)

Would be gratefull for any solution,

best
Ray