[exim] Preserve Spam

Hi,

The organisation are work for are in the process of switching to a new
mail platform. Currently we are researching the following applications :

Exim, Spamassassin, Clamav

Our hope is to run the mail platform both under Windows (through Cygwin)
and in the future under Linux. Therefore it is important that we get as
much similiarty as possible to save time for when we do make the switch
to a Linux mail server.

My question is this. Using the software noted above will it be possible
to filter spam differently for each user (local user preferences), while
also preserving all spam in a "Spam" folder within each users Maildir.
This Spam folder should be available to our users who connect via IMAP.
Users who prefer to remain connecting through POP should be able to
receive all their Spam email only with a rewritten subject.
To summarise we will require 3 profiles of user:

(1) Spam is filtered to a seperate folder which the user can see via imap
(2) Spam is totally unfiltered
(3) Spam has rewrite_subject but is otherwise delivered normally

I appreciate any response and would be interested in finding a contact
for sporadic advice as this project progresses.


Thanks,
David