Hiseas- we also use the SR161 connected to our C80 and laptop. A multiplexer (mux) is needed. Brookhouse (and maybe others) have a model designed for use with the C-series mfd's. Their weblink is here:
NMEA Multiplexer with optional Seatalk-NMEA bridge + USB. If you check their Model AIS-C, they have some discussion regarding the C-series and AIS. Once it's all hooked up, it all works fine.
Steve