I finally got around to configuring the Samba server on the FreeBSD machine. The instructions are here and they couldn't be clearer. One thing didn't work the way the book described it, not big enough to be worth investigating. That's the syntax of Samba commands. Rather than

# smbpasswd -a username

I had to do

# /usr/local/bin/smbpasswd -a username

But other than that, the thing was a breeze. Buy the book if you're thinking of building a server with FreeBSD. It's well worth the price.