keine Ausgabe zweiter Vornamen in Biblatex

[bingo]

Hallo,

welcher Befehl erlaubt es mir bei biblatex nur den den ersten Vornamen und den Familiennamen anzuzeigen?
Der zweite Vorname soll gestrichen werden. Ich finde dazu leider nichts.

Hauptdatei

\documentclass[
    12pt,
    DIV10,
    ngerman,
    a4paper,
]{scrreprt}

\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[
bibstyle=ulm, citestyle=ulm,
firstinits=true
]{biblatex}
\bibliography{Bibliographie.bib}

\begin{document}

\cite{Peters1999}

\printbibliography


\end{document}

cbx Datei

% $Id: verbose-inote.cbx,v 1.7 2011/11/13 19:09:07 lehman stable $

\ProvidesFile{ulm.cbx}
[\abx@cbxid $Id: verbose-inote.cbx,v 1.7 2011/11/13 19:09:07 lehman stable $]

\ExecuteBibliographyOptions{labelnumber,autocite=inline}
\renewcommand*{\multicitedelim}{\addcomma\space}
\providebool{bbx:subentry}
\DeclareFieldFormat[article,book,inbook,incollection,inproceedings,patent,thesis,unpublished]{title}{#1}

\DeclareFieldFormat{entrysetcount}{\mknumalph{#1}}

\newbibmacro*{cite}{%
  \printtext[bibhyperref]{%
    \printfield{prefixnumber}%
    \printfield{labelnumber}%
    \ifbool{bbx:subentry}
      {\printfield{entrysetcount}}
      {}}}

\newbibmacro*{textcite}{%
  \iffieldequals{namehash}{\cbx@lasthash}
    {\multicitedelim}
    {\cbx@tempa
     \ifnameundef{labelname}
       {\printfield[citetitle]{labeltitle}}
       {\printnames{labelname}}%
     \addspace\bibopenbracket}%
  \ifnumequal{\value{citecount}}{1}
    {\usebibmacro{prenote}}
    {}%
  \usebibmacro{cite}%
  \savefield{namehash}{\cbx@lasthash}%
  \gdef\cbx@tempa{\bibclosebracket\multicitedelim}}

\DeclareCiteCommand{\cite}[\mkbibbrackets]
  {\usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\parencite}[\mkbibbrackets]
  {\usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\footcite}[\mkbibfootnote]
  {\usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\footcitetext}[\mkbibfootnotetext]
  {\usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\smartcite}[\iffootnote\mkbibbrackets\mkbibfootnote]
  {\usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\textcite}
  {\let\cbx@tempa=\empty
   \undef\cbx@lasthash}
  {\usebibmacro{citeindex}%
   \usebibmacro{textcite}}
  {}
  {\usebibmacro{postnote}%
   \bibclosebracket}

\DeclareCiteCommand{\supercite}[\mkbibsuperscript]
  {\iffieldundef{prenote}
     {}
     {\BibliographyWarning{Ignoring prenote argument}}%
   \iffieldundef{postnote}
     {}
     {\BibliographyWarning{Ignoring postnote argument}}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\supercitedelim}
  {}

\DeclareMultiCiteCommand{\cites}[\mkbibbrackets]{\cite}{\multicitedelim}
\DeclareMultiCiteCommand{\parencites}[\mkbibbrackets]{\parencite}{\multicitedelim}
\DeclareMultiCiteCommand{\smartcites}[\iffootnote\mkbibbrackets\mkbibfootnote]{\smartcite}{\multicitedelim}

\endinput

Bibliographie.bib

@BOOK{Peters1999,
  title = {W\"orterbuch der Psychiatrie, Psychotherapie und medizinischen Psychologie:
	mit einem englisch-deutschen W\"orterbuch als Anhang},
  publisher = {Urban \& Schwarzenberg <Wien; Berlin>},
  year = {1999},
  author = {Peters, Uwe Henrik},
  pages = {688 S.},
  address = {M\"unchen ; Wien},
  edition = {5., vollst. \"uberarb. und erw. Aufl.},
  isbn = {3-541-04965-0},
  owner = {ingo},
  timestamp = {2013.05.26},
  url = {http://www.bsz-bw.de/cgi-bin/ekz.cgi?SWB06989538}
}

[bingo]

Die Lösung habe ich zufällig gefunden. Ich wollte noch die Kommas zwischen Name und Vorname entfernen und den Punkt nach den Initialien.
Dieser Befehl gibt nur den ersten Vornamen aus.
Man muss ihn nach nach dem biblatex-package einfügen. Welcher Befehl der entscheidende ist, kapiere ich leider nicht:-(

\makeatletter
\def\MKbibnamefirst#1{\expandafter\mkbibnamefirst@i#1..\@nil}
\def\mkbibnamefirst@i#1.#2.#3\@nil{#1}

\renewbibmacro*{name:last-first}[4]{%
  \ifuseprefix
    {\usebibmacro{name:delim}{#3#1}%
     \usebibmacro{name:hook}{#3#1}%
     \ifblank{#3}{}{%
       \ifcapital
         {\mkbibnameprefix{\MakeCapital{#3}}\isdot}
     {\mkbibnameprefix{#3}}%
       \ifpunctmark{'}{}{\addhighpenspace}}%
     \mkbibnamelast{#1}\isdot
     \ifblank{#4}{}{\addlowpenspace\mkbibnameaffix{#4}\isdot}%
     \ifblank{#2}{}{\addlowpenspace\mkbibnamefirst{#2}}}
    {\usebibmacro{name:delim}{#1}%
     \usebibmacro{name:hook}{#1}%
     \mkbibnamelast{#1}\isdot
     \ifblank{#4}{}{\addlowpenspace\mkbibnameaffix{#4}\isdot}%
%     \ifblank{#2#3}{}{\addcomma}%
     \ifblank{#2}{}{\addlowpenspace\MKbibnamefirst{#2}}%
%     \ifblank{#3}{}{\addlowpenspace\mkbibnameprefix{#3}\isdot}
}}
\makeatother