[CA] Interfacing eS-128 to Existing NMEA 2K temp sensor

Hi , How do I display the temperature of an existing NMEA 2k Temp sensor on my eS-128 MFD. This happens to be an ambient air temp. I had an existing NMEA 2K network that is now connected to the eS-128. I see the temp sensor in the NMEA 2k diagnostics . I haven't been able to figure out how to display the temp on a either a chart as an overlay or elsewhere.
Thanks