antispam

[Matthew Broadhead]

in dovecot/conf.d/90-plugin.conf i have
plugin {
   # man antispam
   #setting_name = value
   antispam_debug_target = syslog
   antispam_verbose_debug = 1

   antispam_backend = pipe
   antispam_signature = X-DSPAM-Signature
   # action to take on mails without signature
   # (used with any backend requiring a signature)
   # (we recommend only setting this to 'move' after verifying that the
   # whole setup is working)
   # antispam_signature_missing = move # move silently without training
   antispam_signature_missing = error

   antispam_trash = Trash
   antispam_spam = Junk
   antispam_pipe_program_spam_arg = --spam
   antispam_pipe_program_notspam_arg = --ham
   antispam_pipe_program = /usr/bin/sa-learn
   antispam_pipe_program_args = --username=%Lu
}

it seems to be going into the database ok but it doesn't seem to be 
applying anything it is learning.  might there be some configuration 
option missing?