[plug] Exim mailbox relocation.

[Shayne]

I've been wanting to relocate some mailboxes (via symlinks) to 
our new 80gig monster of the 4gig little guy.

Most things on the deb boxen relocate beautifully, even across NFS.
But exim spits hard on it claiming "not a mailbox" (obviously looking
at the symlink and not the linked to file).

Anyone got any idea. One dude on the server has over 7000 emails
in his inbox!

Also, how does one go about hooking into exim to get it to feed mails
to a particular email box straight into a bit of code. I know it can be
done, but I'm rolling a custom list handler (for a web-portal software
for unions that I'm working on) and need to know how to get it
without ugly hacks like manually parsing the /var/mail directory.