how to add smbuser with default passwd

[ISM Kolemanov, Ivan]

with the 2.0.x samba I've been able to make a script 
which automaticaly was adding unix & samba users from a file
e.g. username=firstlastname passwd=firstname
using useradd, passwd and smbpasswd

How can I do such thing with samba-tng 
I mean automaticaly to create samba user with default passwd
I didn't saw the smbpasswd program :(

10x in advance
Ivan Kolemanov