Are you trying to do some form of Ethernet routing in the TS4W?
Sadly, going Ethernet/IP to serial to the PLC likely won't work, as only the DigiOne IAP has any Ethernet/IP awareness. Plus that code was fairly targeted at AB ControlLogix as-of 2008 or so, and might not handle newer EIP trying to support richer ODVA objects which don't match the ControlLogix defaults.
The best you can do on a normal 'device/terminal server' to bridge Ethernet to serial is encapsulate on of the older serial protocols, such as OMRON HOSTLINK, or Modbus/RTU. (If I remember correctly, TS4W should do basic Modbus/TCP to RTU conversion).