Transfer a makeindex example to a xindy example

Question

I use makeindex for 25 years and I know it isn't perfect. Since xindy is now available also for MiKTeX, I would be happy to switch to this more modern and flexible index processor. Now, I'm looking for a way to make legacy documents work with xindy.

For makeindex, I use a simple style file german.ist which changes actual, quote and level to operate with umlauts in babel:

actual '='
quote  '!'
level  '>'

I need to keep these changes also for xindy since I have a plethora of documents and macros which rely on these settings.

Here is a MWE of a working document with makeindex:

% compiled with pdflatex
\begin{filecontents*}{german.ist}
actual '='
quote  '!'
level  '>'
\end{filecontents*}

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[ngerman]{babel}

\usepackage[makeindex]{imakeidx}
\makeindex[options=-s german.ist -g]

\begin{document}
Test
\index{a}\index{b}\index{"a}\index{"u}
\index{Bart}
\index{B"uro}
\index{Brause>gr"un}
\index{Bach}
\index{Ma"s}
\index{Burg=\textbf{Burg}}
\index{Buch|textbf}
\index{B"arte}
\index{B"ose}
\index{Brause>gelb}
\index{Blind}
\index{Brause}
\index{B"acker}
\printindex
\end{document}

This gives:

Now, I tried to adapt this example for xindy:

% compiled with pdflatex
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[ngerman]{babel}

\usepackage[texindy]{imakeidx}
\makeindex[options=-L german-duden -C latin1]

\begin{document}
Test
\index{a}\index{b}\index{"a}\index{"u}
\index{Bart}
\index{B"uro}
\index{Brause>gr"un}
\index{Bach}
\index{Ma"s}
\index{Burg=\textbf{Burg}}
\index{Buch|textbf}
\index{B"arte}
\index{B"ose}
\index{Brause>gelb}
\index{Blind}
\index{Brause}
\index{B"acker}
\printindex
\end{document}

Here, a counterpart of german.ist is missing. I get the following:

Could somebody help me to get the correct xindy configuration for this example?