MAPI Properties?

I'm using Dovceot/IMAP on Linux and Outlook clients on WIN7 workstations. Mail on Linux is stored in Maildir format.

I'm searching for where Outook keeps its information on color categories in IMAP. According to Diane Poremsky at slipstick.com, "Outlook stores it in the mapi properties of each message. If you use MFCMAPI to viuw the messages, you'll see the properties." MAPI is a Windows thing and the recommended MFCMAPI is for viewing these properties in Exchange. Not what I can use.

Outlook must be storing these properties somewhere in the Dovecot/IMAP system as color categories can be set from Outlook. Can someone tell me where to look for these properties?

THX - Mark