Vigor 2806n

Up until now, I've been able to remotely administer our router on WAN1. Now we a WAN2 connection aswell - Ethernet. WAN2 connects to BT Business Hub, and has been assigned a static public IP address. I can successfully PING this address remotely, and when I disable PING from Internet on the router, the PING stops - so I know the IP forwarding is working OK. However, I don't seem to be able to connect to the management ports using WAN2's IP address. I can still remotely connect to WAN1, but that line won't be live for much longer. Is there a setting preventing me from accessing the management ports on WAN2?

Many thanks,
Steve