Looking at Larry's code example, GPSSource, it looks like you just have to add these to your source to get the KML plugin working:

protected static String[] coordinateChannelNames =
		{"Alt", "Lat", "Lon", "TrackID", "Type", "Classification", "Speed", "Heading"};

Not too bad, think I'll try and add this to SMS-RBNB as a simplest-codebase exercise.