By having the user provide the Copyright KS file that is loaded into an array
of the same size, then replacing only the non-copyright part that you provide
with the program, then saving the result array to a new KS file.
"Every KS I've looked at" is an important qualifier here,
which doesn't include anything other than the hand holding blue disk screen,
so I don't know if anything is done differently since then.
You are saying the screen is drawn programatically so you can't see the image data?
That would be a change since the original screen.
Up until then (at least),
simply ignore the file type an load KS into a program that views the file as a
bitmap with variable alignment and variable (bits per pixel) property,
and play from there.
All intuition graphics (fonts, window borders, default pointer, gadgets etc.)
are clearly visible, and so are the "Amiga", "Workbench", "V1.2/3" bitmaps.
I do know that the original A1000 bootstrap is tight, and they had to make it
The "Amiga" bitmap is still visible in that one though.
I did have a play, but simply not motivated.
I would do it to a real Amiga, but for UAE, I would prefer the original screen.