Would be nice to have a startup script for the dnsextd. The use would  
then set

dnsextd=YES
dnsextd_flags="-z bonjour.example.com -k bonjour. example.com. Ea3+1/ 
r5vsnN8SNCRQeP+Q=="


Here's my suggestion:

#!/bin/sh
#
#

# PROVIDE: dnsextd
# REQUIRE: SERVERS
# BEFORE:  DAEMON

. /etc/rc.subr

name="dnsextd"
rcvar="${name}"
command="/usr/pkg/sbin/${name}"
dnsextd_user="named"
dnsextd_group="named"

load_rc_config "$rcvar"
run_rc_command "$1"