Fit Format for Garmin Dive FIt File

Hi there, 

I'm currently writing a Service that will convert from the common mobile Dive Log apps like Divemate, Diving Log and etc to the Garmin Fit format. I able to get the basic information generated, but in hunt for the Fit Message for setting Conditions like Current, Surface Conditions & Entry. I tried a number of debugging tools like fit to csv, but I have seen any of the fields that I been looking for. Are these Custom Field messages?

Any help will greatly appreciated.