I use Book Designer and Mobipocket Creator.
I find that one has to do some editing, but that Lit is one of the most straightforward conversions.
You might have a look at theis list of BD hints and tips:
https://www.mobileread.com/forums/showthread.php?t=36908
Set the language to German. Check your settings in Configuration/settings, so as to preserve formatting and keep empty lines.
And if BD isn't doing what you require then do try Calibre.