The heading is accepted by the HDS Gen2 touch both when I look at the data source and that it uses it in the nav screen.
The sl2 file tags the heading field as valid both with and without heading data supplied through NMEA 0183 but no data is added, looks like a bug.
The water speed is handled properly, without waterspeed it is tagged as not valid, and when I add water speed over NMEA0183 it gets inserted in the sl2 file and is set as valid.
I will test the new firmware and see what happens!
/hakan