I think for now a possible way to go about it is this:-
1) copy the default theme to you local machine, then rename, then upload new theme to theme folder (not zipped).
2) Click ADD NEW THEME in admin panel themes section, then click on 'create new theme' at the bottom.
3) Go through the steps and ensure Name of the theme's directory is the same as the new theme name.
4) Copy missing files from existing theme choose default bootstrap.
5) Click save. It should now show in the themes section.
This is just a workaround for now..