[exim] Exim to Exchange

I'm looking to use exim, with spamassassin and an anti-virus engine, to
receive incoming smtp traffic for a group of domains, and then forward
them onto a local exchange server.

Having not used exim much before, I'm unsure how to exactly set this up on
the config files. I've had a quick google around, but couldn't find
anything, does anyone have any example config files of how best to set
this up?

Cheers
James