[exim] Exim and Spamassasin: few questions

Hi all,

I have Exim4 set on Debian Sarge and now I'd like to add spam protection
with Spamassasin. Users are getting their mail via pop.
If any of the functionality mentioned below is Exim-specific please advice.

Functionally, I'd like all messages marked as spam to be forwarded to one
account, where an employee could review them manually, forward good
messages to 'notspam@' account that would add them to a whitelist and then
resend to the final recipient.
Additionally, I'd like to have 'spam@' address, where users could forward
bad messages not marked as spam by the system and thus improve the the
learning process.

How can this be achieved?
Thanks for any hints.

-marek

--
Bill Gates to his broker:
"You idiot, I said $150 million on SNAPPLE!!!"