[Samba] how to apply "user must change password at next logon" and "expire password"

[Guido Lorenzutti]

Hi people, i was experimenting with the pdbedit and i found the "user 
must change password at next logon". The thing i wan't able to make it 
work. I just can login and im not asked to change my password! How's that?

The other thing.. i want to make my password expire after 30 days. I did 
this too, but it dosen't apply until i change my password one more time. 
I can make this if i want to apply this on my current samba with 300 
users if i can't force them to change the password or just expire the 
password after 30 days.

Any ideas?

Tnxs in advance.