How does one add document-level JavaScript to a PDF using PDFMark?

I've had success adding annotation-level JavaScript using PDFMark, but the reference doesn't say how to (or if one can) add document-level JavaScript using PDFMark. It seems like you'd want to add it to the Names dictionary in the JavaScript name tree, or in the Additional Actions dictionary, but I haven't been able to figure out the syntax, and I'm not sure if it's even possible.