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{...}.