How do you make spam automatically move to spam group on exit?

[Emerick Rogul <emerick@cs.bu.edu>]

I've configured spam.el to use bogofilter for its spam processing.  To
keep things simple, let's say I have two groups, nnml:inbox and
nnml:spam.

On nnml:inbox, I have the following set via group parameters (BTW, am
I setting these correctly?):

((spam-contents 'gnus-group-spam-classification-ham)
 (spam-process '(gnus-group-ham-exit-processor-bogofilter
                 gnus-group-spam-exit-processor-bogofilter)))

On nnml:spam, I have the following set via group parameters:

((spam-contents 'gnus-group-spam-classification-spam)
 (spam-process 'gnus-group-spam-exit-processor-bogofilter))

When I accidentally receive a piece of spam in nnml:inbox, I want to
mark it as such and have it automatically moved to nnml:spam on group
exit (which I believe is how spam.el is supposed to function, no?)
However, after exiting nnml:inbox, my spam is entered into
bogofilter's database and then expired, but not moved to nnml:spam
(the *Messages* buffer says "Marking spam as expired without moving
it").

What do I need to do in order to move the spam into nnml:spam
automagically?  I think I must be missing something, but I'm not sure
what.

-Emerick
-- 
-------------------------------------------------------------------------
Emerick Rogul             /\/     "how young are you, how old am i?
emerick@cs.bu.edu         /\/      let's count the rings around my eyes."
------------------------------------------------- 'i will dare', the mats