uppercase and mhchem

How do I achieve a proper uppercase including chemical formulas typeset with mhchem, i.e. everything but chemical formulas are capital letters?

MWE:

\documentclass{minimal}

\RequirePackage[paperwidth=70mm, paperheight=20mm, left=10pt, top=20pt]{geometry}%

\RequirePackage[version=3]{mhchem}

\begin{document}
\MakeUppercase{Preparation of \ce{Mn3Ga}.}
\end{document}


output:

which produces MN and GA instead of Mn and Ga, respectively. Please note that I do not want to use $...$ (cp. this question) and \MakeTextUppercase from the textcase package, but the mhchem package and \ce{...}.

The textcase package provides a version of uppercase that is more careful about these things

\documentclass{minimal}

\usepackage[paperwidth=70mm, paperheight=20mm, left=10pt, top=20pt]{geometry}%

\usepackage{textcase}

\usepackage[version=3]{mhchem}

\begin{document}
\MakeTextUppercase{Preparation of \NoCaseChange{\ce{Mn3Ga}}.}
\end{document}