I have the same problem.
German neo layout, got to sublimetext (over humblebundle due to oxeye games studio using your editor (seen in a livestream)).
My return key is mapped on right-alt + p (on english layout right-alt + v) and backspace is right-alt + v (right-alt + w).
I never use the regular backspace, return, movement, delete, page up/down, home, end keys, on some computers I have no mapping for them at all.
My hope is that you can fix it or there is some adon or so that I have not found.
So do I