Resetting A Users Password Through LDAP?

Long story short I have a situation where some users have access to two domains that do not trust each other. They log into one domain and their user ID's are identical on the other domain. So when they change their password on the first domain they need to call into tech support to have it reset on the second domain. I'm writing a app that checks if they have access to the first domain but not the second and if this is found to be true it prompts them for the new password to update the second domain.

Here is where I am stuck. The following code works GREAT but I need it to be more flexible:

Code:

Friend Function ResetPassword(ByVal OldPassword As String, ByVal NewPassword As String, ByVal UserName As String) As String
' Resets a users domain password

[Code]....

The issue is the CN is different between domains (one is first name last, other is last name first) so I need to search by UserID which is the same between the two. So I tried searching by sAMAccountName but it says object not found. Also I need to be able to search the entire Super Corp OU. When I get rid of the extra OU's the search also fails

So I need to search LDAP for sAMAccountName anywhere in OU=Super Corp. How can I do this? Every combination I try seems to fail yet if I hard code it like the above example it works great. The idea is to replace CN=John Q. Public with sAMAccountName=" & username & " to pull jsut that user on the fly.

If it matters all clients are XP SP2 or higher, both domains are Server 2003 or higher. VB 2008 SP1. The error message when a different search is done is a "Object not found".