I must humbly submit that this will work only if you are using 1.3.5 AND copying the classic from 1.3.5. Previous classics will not play well with 1.3.5
Also, and again humbly, I would start with the copying of just the includes/templates/classic/ folder and its contents to includes/templates/whatever/.
Copying files that you have not and will not change only creates more work at the next upgrade. Most of us use a tool like WinMerge when upgrading and it takes a lot less time to compare 30 files than 300. As you modify a file, save it to the override directory. If it is a file in the common directory of template_default, you would then create the common directory under includes/templates/whatever/ and add the file to that directory.
It's not that Kim is wrong or my way is better. I've just trained myself to save the files so I don't have to wonder where the changes are located. If you never touched the tpl_footer.php and the next update did, you would not know without having to compare the override with the update.
Hope I explained that without creating my usual fog.