@XHP -- I thought that a "non-bridged" BlueCurve cable-modem would supply IP-addresses in the "10.0.0.xxx" range in response to DHCP-requests, not IP-addresses in the "192.168.0.yyy" range. So, if the NAS sends a DHCP-request, it should receive a "10.0.0.xxx" IP-address, namely in the same range as other wired/wireless devices connected to the BlueCurve.
Logon to the BlueCurve, and list the "connected" devices -- both their names and their IP-addresses.