How to make ACM style pdfs searchable?

When I create pdfs using the ACM template, searching for and copying umlauts doesn't work. Using cmap gives an error "fontenc already loaded". How can this be fixed?

MWE:

\documentclass{acm_proc_article-sp}

\usepackage{cmap}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\begin{document}

\title{A Sample {\ttlit ACM} SIG Proceedings Paper in LaTeX}

\numberofauthors{1}
\author{
\alignauthor
Ben Trovato\titlenote{Dr.~Trovato insisted his name be first.}\\
\email{trovato@corporation.com}
}
\date{30 July 1999}

\maketitle
\begin{abstract}
This paper provides a sample of a \LaTeX\ document which conforms to
the formatting guidelines for ACM SIG Proceedings.
\end{abstract}

\section{Introduction}

Äöüß fiffy.

The \textit{proceedings} are the records of a conference.
ACM seeks to give these conference by-products a uniform,
high-quality appearance.
\end{document}

-

The developers of the class think that in the last 17 years no progress has been made with fonts.

In lines 1470--1492 they reproduce the package ae.sty, that is obsolete. You can add

\usepackage{lmodern}


to your preamble and solve the problem. The call of cmap is not needed.

\documentclass{acm_proc_article-sp}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}

\begin{document}

-
Do you think anyone will notice that I used a different font when they compile the conference proceedings? – Cephalopod May 4 '14 at 10:48
@Arian They'll probably remove \usepackage{lmodern} if they recompile the document. But it's their business. – egreg May 4 '14 at 11:16