I wonder if someone can help me out of this tight corner.

By putting together seven files I'm trying to create a single composite file. All the seven are written in a similar style. No endnotes, but only footnotes.

1) In one case, when I copy the file and add to the composite file, all footnotes get lost.
2) In another case, footnotes are converted to endnotes.
3) In some other files footnotes have been incorporated into the main text in a smaller font as in the original.
4) In some files added to the composite file, NWP doesn't allow me to add footnotes or endnotes.

Part of the explanation may be that some of the original files have been converted from the Word format and reconverted to the Nisus format. The first file was written more than a quarter of a century ago!
Best wishes, 
Takamitsu MURAOKA