Unable to clear flags in Mail using Exchange 2010

Question

I am able to flag messages without a problem, but when I try to turn those flags off within a few moments it will sync them back to "flagged."  I basically cannot unflag a flagged message.  Connected to an Exchange 2010 server.  Not having any problems getting or syncing mail.  Activity window is clear and nothing is queued up.
I see "changing flags" pop up really quick in the Activity window but as soon as it sync's back up with Exchange those flags come right back.
Help!

Answer 1

I've found a solution that works for me, although it's a little technical.
I found that the Envelope Index file in Home/Library/Mail/V2/MailData/ is actually a sqlite3 database.
the steps I followed were:
Quit Mail (don't know if this is necessary)
Open Terminal, and cd to ~/Library/Mail/V2/MailData/
open the sqlite db using the sqlite3 command line client:
$> sqlite3 Envelope\ Index
Now, in the sqlite3 command shell I queried the messages table to see which messages were flagged:
sqlite> select * from messages where flagged = '1';
I verified that the one message I couldn't clear was in the result set and then I updated the database and cleared the flag:
sqlite> update messages set flagged = '0' where flagged = '1';
Re-start Mail, and voila - flagged messages gone.
Note: to selectively clear the flags from only certain messages would probably require a more advanced update statement that included some join in the where clause.