collecting mail for sa-learn, how to?

[andys]

Hi, 

 for a mail server running email for multiple domains what is the 
typical/recommended way to collect emails which arent detected as spam to be 
processed by sa-learn? Users are downloading mail via POP3, so once a users 
sees a mail and decides that it is in fact spam its already been removed 
from the mail server. If the user forwards the mail to a special mailbox for 
processing then the mail is obviously now different from the original spam, 
the user is the sender etc. Will sa-learn still work using this method? and 
if not what else can I implement that would work? 

thanks for any comments, Andy :P