samba - Apr 2004 - password change on the domain password server using client tools

Hi,

I've setup samba to be a member of a windows 2000 (mixed mode) domain.
I'm using ldap client interface to access the AD on the W2K domain 
controller, in order to add users en groups.

Now, the final step to manage this config is to set the password of the 
users. As it seems hard to use the ldap interface to set the passwords, 
I've thought of using samba client tools, like smbpasswd or pdbedit or net 
commands.

I manage to use smbpasswd -r ADSERVER -U username to set the password 
interactively, pretending being user "username".

Thing is, there should be a way to change (or set initial) password as 
domain admin.

I tried using 

net rap password username "" newpass -U administrator%adminpass

but this doesn't seem to have the intended result (while it doesn't give
me
any indication of success or failure).

So if anybody could give me a clue, how to proceed to be able to change the 
ad password in a scriptable way, I'd be able to finish this integration 
exercise...

Regards,

Lieven