My first attempt failed, mainly because I got confused as to which point in the installation process I should be creating a slice. I was getting an error message that said "partition too big?".
After hanging around the #freebsd chat for a bit and getting a couple of pointers, I tried again. I futzed around with slice sizes for a short time before I finally got it the way I wanted, and ultimately installed it. Unfortunately, when I selected FreeBSD via the BeOS bootloader, it just hung.
So I tried *again*, except this time it froze in the middle the software installation on a package called cvsupit, or something like that.
I'll try yet again tonight and go with fewer software packages.