[XeTeX] Arabic Typography

[Fr. Michael Gilmary]

I have a question about Arabic typesetting. Now, first of all, I haven't 
even learned the whole alphabet yet, so ....

But when I use the Mac font "Al Bayan" with this:

\documentclass[12pt]{article}
\usepackage[no-math]{fontspec}
\usepackage{xltxtra}
\defaultfontfeatures{Mapping=tex-text}
\setromanfont[Ligatures=Common, Numbers=OldStyle]{Garamond Premier Pro}
\newfontfamily\Arabic[Scale=2]{Al Bayan}
\usepackage{bidi}
\newcommand\arabtxt[1]{{\setRL\Arabic{#1}}}
\parindent=0in

\begin{document}

\arabtxt{
يا خبز الحياة   و قوت اﻷرواح   وعربون   النعيم\linebreak
أنت ابن البشر  أنت ابن الإله   والإله هو الرحيم\linebreak
الملائكة قيام  بالخجل والوجل  من بهاك العظيم\linebreak
ونحن المسا كين  كيف نقتبلك  بغمنا ذا الأثيم\linebreak

\end{document}


the text is typeset not only *with* the proper ligatures scripted (Note: 
*without* specifying the Script=Arabic option for fontspec) but also 
will stretch the text with the kashida fillers.

But if I specify the fontspec option (Script=Arabic), then it scripts 
nothing and no kashida.

Am I doing something wrong?

-- 
United in adoration of Jesus, 



fr. michael gilmary, mma

Most Holy Trinity Monastery
67 Dugway Road
Petersham, MA 01366-9725