For the archives:
The solution for me was to use the package cmap (
ftp://ftp.dante.de/tex-archive/macros/latex/contrib/cmap/README )
Now my preamble starts like this:
\usepackage[latin1]{inputenc}
\usepackage{cmap}
\usepackage[T1]{fontenc}
Searching works fine - great!
Thanks for all the hints!
Michael Bierkandt