drop shadow framed environment using mdframed & tikz

Question

I'm attempting to make a drop shadow environment using mdframed and tikz. So far, I have (perhaps naively) tried

\newmdenv[tikzsetting={fill=green!20,drop shadow}]{myshadowbox}

I know that shadow-boxes can be made using fancybox and ntheorem with PSTricks, but I'm particularly interested in seeing a solution using mdframed and tikz.

The MWE below produces a framed environment, and with the rounded corners you can see a shadow has been drawn (in the bottom right corner, look carefully!), but I can't seem to move it- I've tried passing options to drop shadow such as shadow xshift=-5ex but with no success.

So, how can I add and customize a drop shadow when using a newmdenv?

\documentclass{article}
\usepackage[framemethod=tikz]{mdframed}
\usepackage{lipsum}
\usetikzlibrary{shadows}

\newmdenv[tikzsetting={fill=green!20,drop shadow},
                roundcorner=10pt ]{myshadowbox}

\begin{document}

\begin{myshadowbox}
\lipsum[2]
\end{myshadowbox}

\end{document}

Answer 1

Completely EDIT 2012-03-04:

I uploaded the new version 1.3 to CTAN. At the moment the files are available at github.

This version provides a key named shadow. This allows to draw a shadow. The shadow can be manipulated by the new keys shadowsize and shadowcolor

If you use framemethod=tikz it is important to load the TikZ library shadows.

_{mdframed can do the job but I don't want to load any libraries.}

For the methods TikZ and PSTricks I defined a style mdfshadow by tikzset / newpsstyle. For more settings manipulate this key.

Based of the new modification I created the following example:

\documentclass{article}
\usepackage[framemethod=tikz]{mdframed}
\usepackage{lipsum}
\usetikzlibrary{shadows}
\newmdenv[tikzsetting={fill=green!20},
          roundcorner=10pt,shadow=true]{myshadowbox}

\begin{document}

\begin{myshadowbox}
\lipsum[2]
\end{myshadowbox}
\lipsum[3]
\begin{myshadowbox}
\lipsum
\end{myshadowbox}
\end{document}

The result is:

An other example is provided in file mdframed-example-pstricks.pdf which uses pstricks and frametitle:

\documentclass{article}
\usepackage{xcolor}
\usepackage[framemethod=pstricks]{mdframed}
\usepackage{lipsum}

\newmdenv[%
          shadow=true,
          shadowsize=11pt,
          linewidth=8pt,
          frametitlerule=true,
          roundcorner=10pt,
          ]{myshadowbox}

\begin{document}
\begin{myshadowbox}[frametitle={Der Beweis}]
\lipsum[2]
\end{myshadowbox}
\end{document}