Mail 4.4 and Exchange 2010: not staying connected

Question

I am using Mail 4.4 connected to an Exchange 2010 account, and with an SMTP server instead of the actual Exchange connection to send outgoing mail due to the "no from: field" issue.
I have noticed that Mail is not staying connected to the server. IIRC, Exchange is intended to be a live connection, and messages that arrived quite some time ago are nowhere to be seen until I click "Get Mail." Up to now, I've relied on IMAP with IDLE for mail, as I'd rather receive everything in real time instead of relying on a scheduled polling interval.
Why is this? Is it just an issue of being Exchange 2010 instead of Exchange 2007, or is there something I can do to fix it?
My iPhone running iOS 4.2 works perfectly with the same Exchange account.

Answer 1

IMAP with IDLE for mail, as I'd rather receive everything in real time
Certainly in the current version of Mail, you'll get more of a push effect if you use IMAP IDLE instead of EWS for communication with an Exchange server. Exchange Web Services feel less responsive.
The Get Mail routine is much quicker with IMAP IDLE than with EWS. With EWS: the more mailboxes you have, the longer it takes.
However: if you use IMAP instead of EWS, some features of Exchange will appear less graceful. Noticeable with e.g. messages relating to calendaring.
(Note to self: I should review this after our organisation has completed its transition from Exchange Server 2003 to Exchange Server 2010.)
messages that arrived quite some time ago are nowhere to be seen until I click "Get Mail."
Using EWS: in the absence of a real-time/push effect, three approaches come to mind:
a) pull manually (click Get Mail)
b) prefer a schedule
c) simply move or delete any message to trigger an update of that mailbox.
For my Inbox, I prefer (c). An update of the Inbox alone is much faster than the (Get Mail) update of all mailboxes.
Eventually, I guess that Apple will improve Mail to make it respond immediately to changes on the EWS side.
Then, I'll go back to using e.g. GrowlMail to weed most messages immediately, as each one appears (much more pleasing than ploughing through a massive Inbox).