*Periodicals
My reader is set to german, I forgot that that might have another name in english.
I also just solved the problem:
I forgot about the --output-profile flag in the console...
So generating a periodical with calibre works like that:
ebook-convert "Source of your news.recipe" output.epub --output-profile=sony
ebook-meta output.epub --tags="News, Name of your Newssource"
Edit:
It might also work in one step:
ebook-convert "Source of your news.recipe" output.epub --output-profile=sony --tags="News, Name of your Newssource"
(But I'm not sure about that, so i left the old solution)