How to add custom properties to result of patchDocument

[gskaplan]

I need to be able to inject custom properties into the result of a patched document, or, insert them at the same time that the patching is occurring. Currently, my application reads a docx (as the template), then patches it with a bunch of paragraphs, however, I cannot figure out how to get some important data into custom properties that could be accessible in the final document. I've tried to figure out how to convert the patched document back into a Document so I can add the custom properties, but I failed to figure it out. Any help is greatly appreciated.