Add more support for word open xml to access and update like /settings.xml or wordsetting.xml
Thank you for your input, it is greatly appreciated. We are actively adding support for custom and built-in properties so you don’t have to manipulate XML. We’ll let you know when this is available!
Office Extensibility Team
Not sure when it's coming. Till then you can use EDocGen (https://www.edocgen.com). It populates XML into word template and also has a mapper so that you don't have to do any XML manipulation