I do not know the autopilot sk plugin but if it is generating n2k data you can try translating autopilot sentences to nmea 0183 using the signalk-to-nmea0183 plugin. this plugin uses the event "nmea0183out" and you can send this event by your NMEA0183 TX1 connection.
More info about events: https://openplotter.readthedocs.io/en/3....exing.html
More info about events: https://openplotter.readthedocs.io/en/3....exing.html