[Samba] Share-level security; how does it work?

[Fluffles]

Hi guys,

I have one FreeBSD server which will run Samba, and one windows client.
I want the server to have two shares; each protected with their own
password. So once i have connected the windows client to one share, when
i click on the other a password-box should popup; with user-level
security this does not work, Windows will use the same credentials as it
used for the first share. So now i am trying share-level security.

But how does it work? Documentation is lacking in my opinion; and google
did not provide much help too. So i need:

Security = share

in my smb.conf. But what next? Given the two shares:

[alpha]
path=/alpha
writable=yes

[beta]
path=/beta
writable=yes

I would expect i could put a "password = Jr23rJfd" in the share; since
it's share-level security we shouldnt need to work with users. Some
people on IRC said i should use smbpasswd -a, but that would just add
the "root" user to the password database. How does Samba know to which
share this password  belongs? And one samba-user cannot contain two
passwords so how do we create the next password? Why is documentation so
unclear about this?

If any of you guys could help; many thanks!

- Veronica