I'm playing around with your plugin but I'm not sure if it is what I need.
My idea is the following: I need a tool that from selected posts or using a template adhoc in which I add the text or images, is able to generate the newsletter and make it available in a public URL.
That's it. All the funcionality of sending the newsletter will be managed by a different tool, not in WordPress, that will take the HTML of that URL and generate the newsletter.
Is this something I can do with your plugin?