SAMBA should work on MacOS X Beta. The only problem is that there is no available compiled binary configured for MacOS X Beta. The one available through Stepwise is set up for the last developer's release, and folder names have changed a bit since.
Now, if gcc were included, we could just compile from source.
By the way, DO NOT attempt to install the samba binary currently on Stepwise. IT WILL HOSE YOUR SYSTEM. I gave it a shot, and it crapped out in mid-install, because of differing pathnames.