I'm passing this along from the Web page of the BBC radio show Quote... Unquote --specifically, from the page where they look for hard-core missing quotations:

Q621: Heinz Niemann in Berlin seeks the title and further text of a song (probably American) which begins `In the mountain high, way beyond the sky.' It was taken back to his native land in 1900 by a German who lived in Tennessee and became a US citizen.

If you have the answer, you can e-mail it directly if you want to nigel.rees@btinternet.com