Re-mapping the «PowerOff» key on Asus laptop keyboard under Windows 10 64 bits?

Use SharpKeys to see if the Power key generates a scan-code on your keyboard. If it does, then SharpKeys can remap the key in the registry which will work for all programs.
See for tutorial the article Map Any Key to Any Key on Windows 10, 8, 7, or Vista.

In the case that the Power key doesn't generate a scan-code under Windows, then it cannot be mapped, only disabled just as you did. Even if Linux can remap it because it affords better control over the keyboard, this is then not the case for Windows.

The most you can do in this case is to reactivate the Power key and reset it back to do again power-down, and then trap and cancel that event, remapping it to another key such as the End key. This can be done by using AutoHotkey, but may be more trouble than it's worth. If you are interested I can expand my answer to show how this is done.

I do note that sometimes using the Power button is the only way to shut down a hanged computer in a semi-orderly manner.