Exchange <--> Outlook Monitoring

["Doll, Josh" <Doll () pbworld com>]

Is there any effective way of capturing exchange / outlook data from a
3rd party machine?  We have a number of sub consultants with email
access from our company, who's email needs to be monitored / archived
for breech of contract and sharing of company secrets.  Problem is, we
don't maintain our exchange server here in this office, and the office
that does is unwilling to cooperate in this matter (Read: upper
management catfight).  Therefore we need a way to ensure that what they
send and receive is legit.  It is a relatively small number of users
(~5) that are still on our LAN that need to be monitored, the rest have
been moved to another subnet without company email. 

My understanding is that it is nowhere near as easy to capture these
emails when it is an exchange environment vs.. the options available
when using POP or others.

Any help, or nudges in the right direction would be helpful.

C. Josh Doll
Network Administrator - Houston
Parsons Brinckerhoff