I don't think the Nortel can be set up as you said. When we first tried to get this working a local company we use for any Nortel scenarios thought that the above set up would be possible but have since back tracked. I took a 5000 down to their offices and tried to get it working and the engineer suggested the TIE line set up which had the above consequences. Have got 5000's working with Mitel 3300's and Alcatel Oxe's but it seems the Nortel will not work.