Perhaps I'm missing something ...I've been unable to figure out how to create a new document using the EditWrx interface. When it first comes up it prompts me to open a document ...with no way to create a new one as far as I can see. Then when it's opened, it presents me with options to save the current document but no way to create a new one.
Nope. That's the way it works. EditWrx is designed for editing existing webpages. There is no mechanism for creating pages from scratch.
But - assuming your site has some design elements you want on all pages - create a template page. Load the template page and use SaveAs for creating new pages.