User created under Win2K not found under CygWin

I'm new in OpenSource.

I try to use PostGreSQL under CygWin.


I followed Jason's instructions at
http://archives.postgresql.org/pgsql-cygwin/2001-08/msg00110.php

to install it like a Win2K Service.

But Cygwin does not recognise my postgres user created under Win2K.

I think the problem is may be the same for all users because all my
cygwin su <username> commands failed with a problem of invalid password
or user doesn't exist.

May be, do I have to reexecute a CygWin postinstall script to
re-generate /etc/passwd file ?

With mkpasswd -l, all my Win2K users have a unused-by-nt/2000/xp comment
                in place of a * for SYSTEM and Administrators.

Thanks for your help to a novice but motivate user.

Bernard