latin1 characters with lilypond-book -f html

[John Williams]

I am using lilypond book on an html file with latin1 characters in the
lyrics (umlauts, etc).  The latin1 characters are omitted from the output.

I see a few posts about this problem on the lists, but they all seem to
assume a latex source file instead of html.  Does anyone know of a
solution for this with an html source file?

~ John Williams