Because of exec's requesting iPhone support we had to open our IMAP
ports on our Exchange (2003) server. There has been no problems
sending and receiving mail using IMAP except for this issue:

When a user running Windows Mobile 6 on their phone sends the iPhone
user a message the message will not make it to the iPhone. The mail
account displays "Downloading message 1 or 1" or whatever, but will
not show the message anywhere (including Junk or Trash, etc.).

There is no problems at all with users running Windows Mobile 5 on
their phones. The problem only occurs with 6. These same messages
that don't come through on the iPhone show up perfectly in the Outlook
(2003) or Entourage (2004) client, either using Exchange or IMAP, and
if these messages are moved to the trash they still won't show up on
the iPhone.

I find it very odd that I can't find anyone else with this issue.
Apple, after escalating it, said it was maybe a Microsoft issue.
Microsoft, who wanted to charge me $259 to talk to a tech, said they
would either need the $259 or I need to talk to the hardware
manufacturer of the phones running WM6 (even though I can replicate
the same problem running one of their WM6 Pro emulators).

Any help would be nice. Let me know if this needs to be posted
elsewhere.
Thanks a billion.