Hi @Kamil,
thanks for the help, I hope it will work. I have been opened the guvnor repository in the "Dolphin" file explorer and could see all the files inside. Removing of the files was also possible, unfortunatelly all the files were back after refresh :-( So the guvnor webdav interface seems not to be standard implementation.
I checked it and can approve, that the removed files from guvnor repository cannot be put there again with the same filename. I will search for the solution for this. One way i will try is to find the embedded database, check the structure and maybe remove the files directly from the database.