Answered flag is not visible in Outlook when using MAPI

Hello,

we plan to migrate our Mailboxes via IMAP to Exchange, but we have the problem that the Answered flag is not visible in Outlook when using MAPI  to connect to the mailbox. 
I have verified this behavior in Outlook 2003, Outlook 2007 and OWA 2010. When i connect via IMAP to Exchange, i can see the flags, however, when i connect with MAPI, they are not displayed.

Is there a way to display the Answered flag when using Outlook via MAPI?? 

thanks, Marko