Diacritics problem

brief.cls

%%
%% This is file `brief.cls',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% brief.dtx  (with options: `class')
%% 
%% This is a generated file.
%% Copyright (C) 2012 by Michael Wild
%% This file may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either
%% version 1.2 of this license or (at your option) any later
%% version. The latest version of this license is in:
%% http://www.latex-project.org/lppl.txt
%% and version 1.2 or later is part of all distributions of
%% LaTeX version 1999/12/01 or later.
\NeedsTeXFormat{LaTeX2e}[1999/12/01]
\ProvidesClass{brief}
                    [2012/06/27 v0.1
                          Letter class for testing]
\LoadClassWithOptions{letter}
\RequirePackage{ifthen}
\RequirePackage{graphicx}
\RequirePackage{lastpage}
\RequirePackage{fontenc}
\RequirePackage{ragged2e}
\RequirePackage{babel}
\RequirePackage{hyperref}
\DeclareOption{oneside}{\PassOptionsToClass{oneside}{letter}}
\DeclareOption{twoside}{\PassOptionsToClass{twoside}{letter}}
\DeclareOption{final}{\PassOptionsToClass{final}{letter}}
\DeclareOption{draft}{\PassOptionsToClass{draft}{letter}}
\DeclareOption{leqno}{\PassOptionsToClass{leqno}{letter}}
\DeclareOption{fleqn}{\PassOptionsToClass{fleqn}{letter}}
\newboolean{brief@german}
\newcommand{\mypagename}{page}
\DeclareOption{english}{
  \renewcommand{\mypagename}{page}
  \renewcommand{\enclname}{\textbf{Enclosures: }}
  \renewcommand{\cc}{\textbf{CC: }}
  \renewcommand{\ps}{\textbf{PS: }}
  \PassOptionsToPackage{english}{babel}
  \setboolean{brief@german}{false}
}
\DeclareOption{german}{
  \renewcommand{\mypagename}{Seite}
  \renewcommand{\enclname}{}% \textbf{Anlage(n): }}
  \renewcommand{\ps}{}% \textbf{PS: }}
  \renewcommand{\cc}{{Kopie: }}
  \PassOptionsToPackage{ngerman}{babel}
  \setboolean{brief@german}{true}
}
\DeclareOption*{\ClassWarning{brief}{Unknown option `\CurrentOption'}}
\ProcessOptions\relax
\AtBeginDocument{
  \pagestyle{headings}
  \raggedright
}
\renewcommand{\familydefault}{phv}
\renewcommand{\sfdefault}{phv}
\DeclareFixedFont{\x}{T1}{phv}{m}{n}{10}
\DeclareFixedFont{\xb}{T1}{phv}{b}{n}{10}
\newfont{\xiiiv}{phvr8t at 8.5pt}
\newfont{\xiiivb}{phvb8t at 8.5pt}
\setlength{\textwidth}{16.6cm}
\setlength{\textheight}{23.5cm}
\setlength{\voffset}{-0.49cm}
\setlength{\topmargin}{0cm}
\setlength{\headheight}{0cm}%
\setlength{\headsep}{1.45cm}%
\setlength{\oddsidemargin}{-3mm}
\setlength{\evensidemargin}{\oddsidemargin}
\setlength{\hoffset}{0cm}
\setlength{\topskip}{0cm}
\setlength{\footskip}{15mm}
\renewcommand{\ps@firstpage}
{
\renewcommand{\@oddhead}{}%
\renewcommand{\@oddfoot}{\hfill \raggedleft \mbox{\mypagename~\thepage~/~\pageref{LastPage}}}
\renewcommand{\@evenhead}{}\renewcommand{\@evenfoot}{}}
\renewcommand{\ps@headings}
{
\renewcommand{\@oddhead}{\mbox{\ifx\@empty\BetreffTextHead{\ } \else\textbf{\BetreffTextHead}\fi}}%
\renewcommand{\@oddfoot}{\hfill \raggedleft \mbox{\mypagename~\thepage~/~\pageref{LastPage}}}
\renewcommand{\@evenhead}{\@oddhead}
\renewcommand{\@evenfoot}{\@oddfoot}
}
\newcommand{\brief@EinheitName}{}
\newcommand{\brief@EinheitInfo}{}
\newcommand{\brief@PersonName}{}
\newcommand{\brief@PersonAdresse}{}
\newcommand{\brief@PersonInfo}{}
\newcommand{\brief@Ort}{Z\"urich}
\newcommand{\brief@Betreff}{\vspace{-6mm}}
\newcommand{\BetreffTextHead}{\vspace{-6mm}}
\newcommand{\EinheitName}  [1]{\renewcommand{\brief@EinheitName}{#1}}
\newcommand{\EinheitInfo}  [1]{\renewcommand{\brief@EinheitInfo}{#1}}
\newcommand{\PersonName}   [1]{\renewcommand{\brief@PersonName}{#1}}
\newcommand{\PersonAdresse}[1]{\renewcommand{\brief@PersonAdresse}{#1}}
\newcommand{\PersonInfo}   [1]{\renewcommand{\brief@PersonInfo}{#1}}
\newcommand{\Ort}          [1]{\renewcommand{\brief@Ort}{#1}}
\newcommand{\Betreff}    [2][]{\renewcommand{\brief@Betreff}{#2}%
\ifthenelse{\equal{#1}{}}%
{\renewcommand{\BetreffTextHead}{#2}}%
{\renewcommand{\BetreffTextHead}{#1}}
}
\let\UnitName\EinheitName
\let\UnitInfo\EinheitInfo
\let\PersonAddress\PersonAdresse
\let\City\Ort
\let\Subject\Betreff
\let\subject\Betreff
\renewcommand{\opening}[1]{%
  \thispagestyle{firstpage} % Special style for firstpage
  \setlength{\unitlength}{1mm}
  \begin{picture}(166,63)
    \put(-1,88){
      \begin{picture}(0,0)
        \put(98,0){\makebox(0,0)[lt]{%
          \begin{minipage}[t]{68mm}
            {\xiiivb \brief@EinheitName}\\[4mm]
            {\xiiiv \brief@PersonAdresse}\\[4mm]
            {\xiiivb \brief@PersonName}\\
            {\xiiiv \brief@PersonInfo}
          \end{minipage}
        }}
      \end{picture}
    }
  \end{picture}
  \par
  \brief@Ort, \@date
  \par
  \ifx\@empty\brief@Betreff\else\textbf{\brief@Betreff}\vspace{5mm}\fi
  \par
  {\x #1}
  \par
  \flushbottom
}
\renewcommand{\closing}[1]{\par \ \par \nobreak%
  \stopbreaks
  \noindent
  \ifx\@empty\fromaddress\else
  \hspace*{\longindentation}
  \fi
  \parbox{\indentedwidth}{\raggedright
    \ignorespaces \x #1\\[6\medskipamount]%
    \ifx\@empty\fromsig
    \fromname
    \else \fromsig \fi\strut}%
\ \par
\ \par
}
\endinput
%%
%% End of file `brief.cls'.

test.tex

\documentclass[german]{brief}

\EinheitName{XYZ Departement}
\EinheitInfo{SSS}
\PersonName{Felix Muster}
\PersonAdresse{%
  Universit\"at AAA\\ Geb\"aude XX\\
  Beispielplatz 5 \\ CH-8000 Z\"urich%
}
\PersonInfo{%
{\setlength{\tabcolsep}{0mm}
\begin{tabular}{@{}l@{~}l@{}}
Tel   & +41-44-63 2a aaa \\
Fax   & +41-44-63 2a aab\\
Mobil & +41-79-59 aa bbb\\
\end{tabular}    }\\[0.6ex]
fmuster@aaa.ch\\
www.muster.aaa.ch
}
\Ort{Z\"urich}

\signature{Felix Muster}

\Betreff{Beispiel f\"ur Briefvorlage}


\begin{document}

  \begin{letter}{Johanna Beispiel \\
                 Industrieweg 1 \\
                 ACME Corp. \\
                 9999 Ort}
    \opening{Liebe Frau Beispiel,}

    Nunc congue mauris non justo dapibus a condimentum sapien convallis.
    Vivamus dictum tristique imperdiet. Nulla facilisi. Donec id nunc lacus, in
    aliquet arcu. Nullam dapibus urna sem, quis vehicula arcu. Proin eget nisl
    sem. Pellentesque habitant morbi tristique senectus et netus et malesuada
    fames ac turpis egestas. Vivamus urna nisi, venenatis quis interdum vel,
    varius quis sapien. Donec risus nibh, facilisis in laoreet eleifend,
    volutpat id massa.

    Donec placerat, nulla vel lacinia ultricies, nulla dolor accumsan purus, ac
    laoreet massa tellus pharetra ligula. Vivamus lobortis placerat quam, nec
    dapibus ligula aliquam et. Nullam ut nunc quis orci fringilla pellentesque.
    Nam semper tempus metus sit amet tincidunt. Praesent tempus mi ac erat
    porttitor semper. Vestibulum ante ipsum primis in faucibus orci luctus et
    ultrices posuere cubilia Curae; Nulla mattis luctus enim, eu venenatis est
    porttitor in. Nulla vulputate erat a eros tincidunt tincidunt. Sed
    convallis quam quis felis molestie nec mollis lorem ultrices. Donec orci
    sapien, euismod eget venenatis sed, pulvinar ut mauris. Maecenas vehicula
    dapibus dui porttitor vulputate. Praesent eu elementum mauris. Nullam nisi
    metus, cursus in sollicitudin vitae, venenatis sed massa. Praesent bibendum
    turpis sit amet odio condimentum adipiscing. Etiam at euismod elit.
    Vestibulum a risus velit, ac aliquet dolor.

    \closing{Mit freundlichen Gr\"ussen}

    \cc{Kopieempf\"anger 1, Kopieempf\"anger 2}
    \encl{Beilage 1 \\ Beilage 2}
    \ps{Irgend ein Text am Ende der Seite.}

  \end{letter}

\end{document}