You can add the PIX via an snmp accessible address and then use the read-only community string in the device credentials when adding the device into
RME 3.5 or the DCR (LMS 2.5)
You also need to make a device configuration to allow snmp access:
a. snmp-server host where x.x.x.x is the IP Address of CW2K server and interface is where the CW2K server packets will come through
b. snmp-server community
HTH