Vista - How do I change domain account password

I have service accounts that I use to run SQL Server services.

I run powershell from my local machine using my login USERDOMAIN\myid

I want to change the password for the service accounts that reside in a
different domain PRODDOMAIN\svc_account1. I have permissions to change the
service account passwords, and I am able to change the password using the
windows server tool "Active Directory Users and Computers" . I cannot get
the password change to work using Powershell.

I want to avoid having to install the quest cmdlets.

I have searched quite a while and this code snippet seems close to what I
need.

$password='NewPWValue1'
$user = [ADSI]"LDAP://CN=svc_account1,OU=Service Accounts,OU=User
Data,DC=proddomain,DC=mycompany,DC=com"
$user.Invoke("SetPassword", $password)
$user.pwdLastSet = 0
$user.SetInfo()

I get this errormessage when I run that code:

Exception calling "Invoke" with "2" argument(s): "Member not found.
(Exception from HRESULT: 0x80020003 (DISP_E_MEMBERN
OTFOUND))"
At line:1 char:13
+ $user.Invoke( <<<< "SetPassword", "NewPassword123")
If I do end up using the ADSI, is there a way to translate t he PRODDOMAIN
to the FQDN as in PRODDOMAIN.mycompany.com

If you have a better script that works that would be fine.

Please help if you can.