We are working on support for bookmarks right now. It will be possible to navigate DocumentBuilder to a bookmark and insert content at that position. Please check back in a week or so - it will be ready by then.
Thanks for getting the bookmark support in Aspose.Word - great !!
One more thing, any chance that you can expose a collection or array or bookmarks that are in the document ? This would make the project I’m working on a snip to do.