Send As Won't Work

[JohnE66]

I am trying to get the "Send As" privilege working and have followed the instructions in MSKB 327000.

http://support.microsoft.com/?kbid=327000

But I keep on getting the error:

"You do not have permission to send to this recipient."

I have also set up both users with full permissions rather then just the Send As....but still no joy.

Domain Admins have no problem doing a Send As someone else.

Any help would be gratefully received.

Thanks