DHCP site specific vendor options?

[gsgleason]

I'm currently using ISC dhcpd on a seperate linux server with site specific options for IP phones.  I would like to move this responsibility to pfsense.

I can't find a way to add site specific options via the web, and if I manually edit /var/dhcpd/etc/dhcpd.conf from the pfsense shell, all changes go bye bye after using the web interface to make any dhcpd changes.

Is there a way to do this at this point?