bogofilter on remote host

[cyph]

Hello everyone, 

I'm using bogofilter on a remote server to filter mails before they enter the 
user's Maildir. After retrieving the non-spam mails to my local machine via 
POP, I'd like to train the remote bogofilter with those messages classified 
as ham incorrectly. How could I do this? 

One idea was that the user could redirect incorrectly classified messages from 
his local machine to some special address "spam at domain.com" on the mail 
server, and configuring the mail server such that it pipes all messages 
arriving at this address through bogofilter -N -s. 

First question: Is there a more elegant solution to this? Does anyone have 
scripts etc for this purpose? On the mailserver, I'm using exim4 and 
procmail. 

Second question: The redirected mail which will get piped through 
bogofilter -N -s will have additional headers due to the redirection (like 
Resent-From, Resent-To, Resent-Date, Resent-Message-ID), though the original 
From, To, Subject headers remain unchanged. Does bogofilter care about these 
new/additional headers? Is there a list anywhere, which headers are relevant 
to bogofilter and which ones are ignored? 

Thanks alot, 
Rainer