Best way of moving mail server to new external IP

[ktindall]

I've been running our Zimbra install (7.0.0_GA_3077.RHEL5_64_20110127190222 CentOS5_64 NETWORK edition) out of our office, but we recently bought a rack in a colo center and I want to move it over there. My current idea is to shut down the current Zimbra install, copy it over to the colo and then set up the one in the office as a secondary server according to the section in the split domain article (Split Domain - Zimbra :: Wiki). Am I correct in assuming this will deliver messages to the new server until the new MX record propagates? Also is there a way to forward the web interface on the old system to the new one while the record for that propagates as well ? Is there any legal issues with temporarily running two network edition installs? If any one else has any other ideas on how to do this in general I'd like to hear it.