Westi, thanks,
But this NUSN (which stands for NO USER SOURCE NUMBER...) is to disable DMP between different type of phones (h323-sip).
The point is, in my setup I' m using now, our SIP phones has two IP adresses (from the looks of the IP Office).
Phone one has public IP 192.168.3.xxx and private IP 10.90.0.xxx (where xxx is the same).
phone two (which is in the same location) has public IP 192.168.3.yyy and private IP 10.90.0.yyy (where yyy is the same).
Now, as designed by avaya, and mentioned in the help file, DMP can only been done when both phones has the same public IP, which in my setup is not the case.
So what I need is a NUSN that overrides that behaviour..