[Samba] Accounts/Passwords How does it work?

[Darryl Harvey]

I am getting very lost.

I have a bunch of existing linux users.

I want them to also be able to use the samba shares..  How do I easily
get there usernames/passwords for access via samba?

I have the following set;
   encrypt passwords = yes
   smb passwd file = /etc/samba/smbpasswd
   unix password sync = Yes


At present I manually add each one with smbadduser, 
But that prompts me for their password.

I haven't a clue what their passwords are and I do not want to start
telling them that I have set it.

Is there a way to;

1/. Add/Import existing users without changing the passwords (IE: keep
them sync'ed whether they change them in linux, or in samba)

or

2/. Add a user to the system so they are both linux and samba users in
one go ?

The docs are very vague here...
What are my options?

Thanks
Darryl