Parsing Outlook 2011 message

I would like to extract the Imap uid of an Outlook 2011 message.
If I select a random message in one of the folders of my mailbox, I see that the message has an “Exchange ID”, but not an “IMAP UID” (it’s actually = 0).

The reason behind why i need this data is the following.
I run a filemaker database, in which in which i can load all mails. The communication happens directly between filemaker an the Exchange server. I use the plug in “Mailit 5” to do this.
Importing the message as such leads to a .msg format.
As I’m on Mac, I’d prefer to have an .eml format, but this is not possible with Exchange.
So the work around is to grap the imap uid, search for it in Outlook 2011 for mac, and move the found message as .eml file in the right location. But strange enough the outlook message have no imap uid.

Any ideas how this can be solved?