Why is texlbl attribute sufficient for node, but not for edge in dot2texi?

Question

I'm using dot2texi to embed mindmaps (= graphs) with arbitrary latex markup in nodes and on edge labels in latex documents (compiled with pdflatex) which should be layout completely automatic. Atfter experiencing great results with nodes. I'm wondering why my edge labels are not displayed when they are in the texlbl attribute. Please take a look at the following example:

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}

\usepackage{dot2texi}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\usepackage[german, ngerman]{babel}
\usepackage[babel, german=quotes]{csquotes}

\begin{document}
\begin{dot2tex}[tikz,autosize, scale=1.0, dot]
  digraph G {
    A [texlbl="\begin{minipage}{5cm}ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP ABCDEFGHIJKLMNOP \end{minipage}"];
    B [texlbl="B"];
    C;
    A -> B [texlbl="\begin{minipage}{10cm}abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvw \end{minipage}"];
    C -> B [texlbl="\begin{minipage}{10cm}1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 \end{minipage}"];
    B -> C;
  }
\end{dot2tex}
\end{document}

Adding the tikzedgelabels option causes horrible layout.

When I add label=" " to the edges, the layout happens with dot layout but is errornous with circo, neato, twopi and fdp.

What am I missing?

EDIT: this is a pending issue which will be part of dot2tex 2.9 (see https://code.google.com/p/dot2tex/issues/detail?id=18 for details)