I'm using latest version of Zimba ZCS 6.0.10. Big thanks for really hard work guys! Zimbra ROX!

I have one quite big problem related to my IP address. Right now I have 4 IP's on my dedicated server. Unfortunately the main IP has been blacklisted because of the problem with revDNS. I'm working with the ISP to resolve the problem but 3 other IP's are 100% OK (with the REV DNS). Also my question is: how to force Zimbra to use backup IP (which is already configured as eth0:1) as the SMTP outcome (from the Zimbra to the internet) traffic ?