This documentation is not using the current rendering
mechanism and is probably outdated.
The extension maintainer should switch to the new system.
Details on how to use the rendering mechanism can be
Launch Direct Mail! launches the four newsletter categories:
The forms for subscribing and update contains all categories but the default one.
If you want to switch from multiple newsletters to a default one, you have nothing to do
than to disable the powermail field, which is called “newsletter”.