DNS Blacklists and iPhones\Mobile Devices

I use my iPhone with IMAP to connect to our Domino server. On our Domino server we use the Spamhaus Zen DNS Blacklist to tag emails and then an agent places the email in users’ Junk folders. My iPhone sometimes picks up an IP address that is on the Zen Blacklist, which results in my emails sent from the iPhone to other Notes users ending up in their Junk folder.

I could try to get the IP removed from the DNS Blacklist but that could be an everyday event as the IPs change regularly. Then it occurred to me that I could whitelist our own Domino server so that iPhone and Windows Mobile IMAP clients sending through it skip the DNS Blacklist check. But that isn’t working. I had wondered if a server can be on its own whitelist. Apparently not. (The info about this option says it “Applies only to hosts subject to inbound relay enforcement” so I take it to mean the Domino servers in a domain are not subject to the same enforcement rules as connecting SMTP servers). Any suggestions on a way around this or another solution?

Thanks in advance,

Greg