WNR2000v2 doesn't detect connection on WAN port (to Alvarion IDU)

I'm trying to use WNR2000v2 to connect to Alvarion IDU but it doesn't detect the connection on WAN port.
Also when I connect Alvarion IDU to any of the LAN port it's not detected.

- It works fine when I put an HUB switch between WAN port and IDU
- Just to be sure I tested also with a cross Lan cable but no changes
- Main problem is that doesn't detect the physical connection when connected directly



- Alvarion IDU is working fine with direct PC connection and with all routers that I tested up to now: two Linksys and one Digicom - With all those tested I'm assuming it doesn't have issues.
- WNR2000v2 is working fine when connected to ADSL modem

I reset it to factory default multiple times but no changes

Best regards