I have FreeBSD 8.0 installed on my laptop and a PC at home.
I'm currently at work without my laptop. So I can't give EXACT syntax I used for mounting the BSD partitions when booting with Linux.
I do remember that specifying the filesystem as "ufs" didn't work.
I seem to recall the filesystem type had a "2" in it's name.
mount -t u2fs /dev/somedevice /mount/point