[exim] Exim and Exchange Server Configuration?

I am setting up exim on my linux box to connect to an
Exchange Server here at work. I have it properly forwarding
mail, but the others in the company see mail as being
received from:

'"Morris, David" [dmorris@???] on behalf of "David Morris" [dmorris@???]'

I need the Sender to appear as if I sent the mail from
Outlook in that is says it is from "Morris, David", and when
you double-click on the name in outlook it brings up the
user information queried from the Exchange server rather
than the SMTP address information.

Any tips on how to set this up?

    exim 3.35
    Mutt 1.3.28
    Exchange Server (unknown version, probably 2003)

--David