Auto-complete list pruge internal employee

Hey everybody,

I got a problem with terminated employees and the auto-complete list (old nk2). 

The terminated employees are still in the list and it looks like I only can delete them manualy. 

Is there any possibility to compare the content of the list with the GAL and delete the wrong addresses? 

In this article a way is discribed but the first step isn't viable imo. 

1. Exit Outlook, and then close Outlook Web Access or Outlook Web App (OWA) on all workstations that are connected to your mailbox.

http://support.microsoft.com/kb/2679568/en-us  (@How to export the auto-complete mailbox message)

I would like to use a skript or maybe a smarter way but I'm not able to find sth. in the web. 

Kind regards

Paul