Apparently there is no single correct description of how to convert a codebase from Subversion to Git on the whole of the internet. On MacOSX, we could not connect over svn+ssh protocol to the old repository; with the OpenSUSE Linux distro we had better luck, but a lot of the described actions in several posted articles were just incorrect. In the end we have settled for a git svn clone action, pushed to a bare git repository, did a lot of copying and renaming, and pushed all branches from there to the git repo on SF.