how to add flags to an rc.d script

["James K. Lowden" <jklowden%schemamania.org@localhost>]

Hello, 

I installed mail/spamd and copied /usr/pkg/share/examples/rc.d/pfspamd to
/etc/rc.d. 

I would like to have the command issued by the script use the '-g'
(greylisting) flag.  When I change:

        command="/usr/pkg/libexec/spamd"
to
        command="/usr/pkg/libexec/spamd -g"

I get an interpreter error.  When in rc.conf I change

        pfspamd=YES
to
        pfspamd=YES  pfspamd_flags="-g" # greylisting

there is no effect.  

What is the right way to do this?  I didn't find anything in TFM for
rc(8).  

Many thanks.

--jkl