It seems that my question attracted one of those crusaders - even though the answer will like involve a 'software' solution, I described my question clearly with the title "copying/editing text containing null characters on Windows".

@prusswan more context would be useful

@prusswan your question isn't actually very clear to me and the comments read like a circular argument

"I know there's some reason why this doesn't work because of a fundamental problem with the windows clipboard but I don't want to use other tools because I want to use the (obviously broken) windows clipboard that I know will never work"

Is essentially how the comments make it sound. The question itself could be clearer, and the samples you've given are not relevant because Windows != Linux and you've already stated that for your data the Windows clipboard is broken.

More detail, such as why exactly this is a problem, might be useful. Maybe what kind of solutions are workable might help. Would some other software work? Maybe a dirty hack to replace nulls with a FIXNULL string, copy to clipboard, paste into new and then re-replace the nulls?