just downloaded the newsletter plugin + installed it. I also followed the instruction on the add ons but the plugin still shows them as not installed (reports, followup). Feed by Mail seems likely to work – at least I can see the change that occured on installing the plugin add on.
All add-ons are in the newsletter plugin folder (I unziped them and uploaded the folders onto the newsletter plugin (1st level folders)
Yes, they are not plugins, they are standalone components. If you put them on newsletter folder, other than not work at all, they will be deleted on next newsletter update.
I figured it out myself already. Thing is, you have to put the stuff in wp_content/extensions (even if your wordpress doesn’t have such a folder, then you have to create it).
All my plugins are usually saved in wp_content/plugins.