[texhax] Using letter for subsection numbering but keeping section/chapter numbering

[Pascal]

Hi all, 

I would like to have letters for 'numbering' my subsections, but still
keep the chapter-section numbering in front of it like 2.3.a SUBSECTION
FOO-BAR

When I use: \renewcommand*\thesubsection{\alph{subsection}} I only get
the letter, but no the section/chapter numbering

Here is a somewhat minimal example:

\documentclass[
11pt,		
paper=a4,	
ngerman,	
BCOR=0pt,	
DIV=calc,	
headinclude,	
headsepline,	
]{scrreprt}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[sc]{mathpazo}


\typearea[current]{calc}

\usepackage[ansinew]{inputenc} 

\renewcommand*\thesubsection{\alph{subsection}}

\begin{document}



\tableofcontents


\chapter{One}

\section{Eins}

\subsection{Un}

\section{Zwei}

\subsection{Deux}

\end{document}


In case you have typographical/logical objections to my desire of using
letter for subsection, feel free to suggest better solutions. It's just
that I find using three numbers 'in a row' a bit tedious to read.

Thanks for your help, 

Pascal