Is it possible to create a trace of the incoming serial data from my devices?

Yes this is possible. Since Hydromagic version 6.0.14.727, all incoming serial data received using either a NMEA0183 channel or plugin is recorded to the raw data files when recording.
You can simply export this data to a text document, by right clicking the original raw data file and selecting the "Trace..." option from the popup menu that appears.

The data will appear in notepad, to store the data, select "File" => "Save As..." from the notepad application.