Well, it looks like I solved the problem (with some very good and prompt help from the AutoHotkey community): You download the free program AutoHotkey (from https://autohotkey.com). This is quite a complex and very capable program, but you only want it for one simple purpose. Go to the tutorial and read about how to make a script. Then copy the following into your script
===========
Starting here: >
#NoEnv ; Recommended for performance and compatibility with future AutoHotkey releases.
SendMode Input ; Recommended for new scripts due to its superior speed and reliability.
SetWorkingDir %A_ScriptDir% ; Ensures a consistent starting directory.
#IfWinActive ahk_exe wpwin17.exe
Numpad7::
NumpadHome::
Send ^!+{F9}
; Send {ctrl down}{shift down}{alt down}{F9}{alt up}{shift up}{ctrl up}
Return
^Numpad7::
^NumpadHome::
Send ^!+{F10}
; Send {ctrl down}{shift down}{alt down}{F10}{alt up}{shift up}{ctrl up}
Return
< And ending here.
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What this script does is to assign the key Ctrl-Alt-Shift-F9 to the Home key on the numeric keypad AND assign the key Ctrl-Alt-Shift-F10 to the Ctrl-Home key on the numeric keypad. The assignment only works in WordPerfect (X7), everywhere else in Windows Num-Home and Num-Ctrl-Home work normally. -- After running the script, the physical Num-Home and Num-Ctrl-Home keys are actually Ctrl-Alt-Shift-F9 and Ctrl-Alt-Shift-F10 respectively, and you can assign any value you like to them within WordPerfect.
In the same way, you can differentiate between the cursorpad's and the numeric keypad's arrow keys. Get AutoHotkey to change the physical cursorpad RightArrow to the value Alt-Ctrl-Shift-F12 or something, and then when you assign a new value to Alt-Ctrl-Shift-F12, it will only effect the cursorpad RightArrow, not the RightArrow on the numeric keypad.