The regular save files should be working, but you have to save in them manually. If you've unzipped the files to a folder you have permissions to add or alter files in, there shouldn't be any issues with saving. If you continue to have issues, could you describe the exact process you go through when saving and where the problem occurs? You should just be able to open the Save Menu (not the Load Menu, which looks similar) and click on one of the save slots, which look like comic books.