Unfortunately, Microsoft excluded support for Exchange 2003 in Office 2011 for Mac.
I thought that at least we could get e-mail operational through IMAP to the 2003 server, but found that the inbox subfolders would not show up.
I found this article on using Davmail which once installed showed up all the IMAP folders. Davmail acts as a proxy to outlook web access, see you can figure it your local outlook to connect to the local Mail server which then seems the requests through to the exchange 2003 server.
Here are the instructions
- Download and install DavMail for Mac OS/X on your Mac from-