How to create a new Sport?

Hi

I'm trying to create a new activity type for Windsurfing. I did the following steps, but I cannot find the new activity in my Fenix 6 Saphire:

1. Copy GARMIN\Sports\Wandern.fit to the directory, where the FitCSVTool.jar is
2. java -jar FitCSVTool.jar -b Wandern.fit Windsurfen.csv
3. Edit the csv file: change sport 17 to 43
4. java -jar FitCSVTool.jar -c Windsurfen.csv Windsurfen.fit
5. Copy Windsurfen.fit to GARMIN\NewFiles
6. Started the Fenix but cannot find the activity type

When I connect the Fenix to the computer again, the folder GARMIN\NewFiles is empty. In the folder GARMIN\Sports I cannot find Windsurfen.fit. I also tried to copy Windsurfen.fit to GARMIN\Sports but it does not work.

Whats going wrong here?