Question about DNG for importing document as a module
One answer
You expect to use two requirement tools in parallel and somehow "merge" the requirements together, which is not supported. If you're so reliant on Word, the best choice could have been RequisitePro but it's long gone.
As you have discovered, after you "extract" the requirements from a text document, DNG has no knowledge of the original document at all, and there is no way to map the requirements back to the document. The only way to support a "round trip" editing (or offline editing if you prefer) is use CSV but that is not what you want as you are talking about charts.
If charts is the main concern, you can do it this way - as most charts are converted to images during the import, you can always upload a "newer version" of the image/chart.