Connect the one from tip of the plug to the original inner core terminal and the other inner wire (that goes to the new plug ground) to the original screen terminal.
Trim the excess screen back just clear of the terminals; it does not connect at the input end.
That style of wiring supposedly gives a better result as the screen is only connected at the amp end, so not taking any current from the signal (or something like that).
I doubt it will make any difference, but it does not hurt anything.