rc.conf.local

You need a rc.conf.local in your /etc directory. By default, it is not there.
The rc.conf.local is basically a local extension of your rc.conf file. Instead
of editing the rc.conf file directly, you edit rc.conf.local and put your
settings there.

for example, in my rc.conf
wsmoused_flags=NO

so, to enable it, I would put in rc.conf.local
wsmoused_flags=""