This does work in pfSense 2.3.2:
1. Make sure "enabled" key is set to "yes" in /etc/pkg/FreeBSD.conf
2. Change "enabled: no" to "enabled: yes" in /usr/local/etc/pkg/repos/FreeBSD.conf
3. Change "enabled: no" to "enabled: yes" in /usr/local/etc/pkg/repos/pfSense.conf for FreeBSD repo
4. Now you're able to install packages from FreeBSD official repo
1. Make sure "enabled" key is set to "yes" in /etc/pkg/FreeBSD.conf
2. Change "enabled: no" to "enabled: yes" in /usr/local/etc/pkg/repos/FreeBSD.conf
3. Change "enabled: no" to "enabled: yes" in /usr/local/etc/pkg/repos/pfSense.conf for FreeBSD repo
4. Now you're able to install packages from FreeBSD official repo
https://forum.pfsense.org/index.php?topic=109827.msg644067#msg644067