Kali's base is with Debian Testing and the backports repository is not made available in the default install. I would not be monkeying with it.
you need to make a decision, whether to continue this Thread, and close the one at linuxquestions.org or vice versa.
We don't mind which choice you make, but you may not realise it is bad manners to have the same thread being pursued at two or more different forums - we cannot read minds on what is being said there, and they with here.
Let me know ASAP.
Helpers I would advise waiting until the OP responds to me. Thank you.