samba - Jan 2005 - changing user password by using passwd command

Hi List, 
 
I am using AD authentication by using winbind and it is working fine .
One problem is, after authenticating to a Linux machine by using AD user
name & password , the user is unable to change his/her password by using
passwd command. 
 
I want know , actually it works (or) not? 
 
 
Regards, 
shashi kanth