Any way to make my manual DNS changes persist?

[pgentoo]

I'm planning a migration this weekend, and I have a few outstanding concerns. One of which is that I have a few clients who choose to run their own mailservers (they have Exchange server in the office), so i have to point their MX entries at their IP. A few others choose to have me run their mail, but want their site run elsewhere.

Since there is no DNS management in ISPCP yet, I'll have to manually edit their zone's to get this to happen. That's fine, but what all do I need to do to insure these changes will not be overwritten? Is copying the zone to /etc/ispcp/bind/working/ enough? Or is there no way to stop these files from being overwritten if the zone gets rebuilt down the road?

Thanks,
pgentoo

Note: I can't wait for built in DNS management.