sending files recursive per SFTP with JCraft doesn't work properly

sending files recursive per SFTP with JCraft throws an error if a subfolder already exist or you have more than one file in a subfiolder.
After the subfolder is created for the first file it tries to create the subfolder again for the second file and here it gets an error.

WORKAROUND:
use the parameter

target_load_class_name=com.sos.VirtualFileSystem.SFTP.SOSVfsSFtp