[Samba] passdb requires /etc/passwd entry?

[Gabor Kiss [Bitman]]

> I can't comment on the intentions of the samba authors as to the reasons
> that they have required the samba user to be a local unix user. I would
> venture to guess that a search of the samba archives would give you a
> lot of history on that.

OK, but I want at least these unix accounts to be locked.
So samba password is different than stored in /etc/shadow.
However these users cannot use swat at this moment because
it checks the normal unix password instead of samba content
of /var/lib/samba/secrets.tdb.

How can I reach swat to ignore /etc/shadow?
(It is no LDAP here.)

Gabor