using systemwide Bogofilter AND user Bogofilter together

[Pollywog]

I set up Bogofilter systemwide, to run from /etc/procmailrc, but
when users have their own Bogofilter setup, it does not work.
I thought that individual users could override the system Bogofilter
by having their own ~/.bogofilter installed.  Is there a way to get
it to work?  I did add the following to my /etc/bogofilter.cf:

user_config_file=~/.bogofilter/config


thanks