Am deploying iredmail pro for one of our clients.
They have an existing exchange system but want to migrate some of the users onto iredmail and use both the systems parallely.
we have deployed a test version of excahnge 2007 and iredmail free edition in our lab for testing out the scenario,
Its installed on redhat 6.0. iredmail version is 0.7. Mail accounts are stored in MySQL.

On exchange 2007 the domain has been set to relay mode and a separate send connector has been made for delivering mails to non-exchange email id's onto iredmail. this is working fine.
On the iredmail server - the main.cf file has eben edited to ensure that all outbound mails are relayed to exchange 2007 server and from there mails are delivered to the outside domains.
from outside i am able to receive mails onto an exchange user as well as an iredmail user.
from exchange server am able to send mail to a iredmail user.
from iredmail i am able to send mail to an outside domain successfully - however if i try to send a mail to an exchange user - then it fails.
both the exchange and the iredmail server share the same domain space.
while trying to send a mail to exchange user - it tries to lookup the user in its local database and returns an error saying local user unknown.

i need help in this regard so that we can deploy the solution.

Thanks in advance