I wouldn't really say that (I mean the In Kraut stuff) is schlager at all. Maybe the Hildegard Knef stuff which is definitely good.
I'm sure I've stuck this up before but I believe that Cindy und Bert were known as a schlager act before they came up with this monster (or camp monstrosity depending on your taste - I'm in the former group)
Christ. That's more ticks than I've got boxes I think! Love it.