[XeTeX] Font selection problem

[Haines Brown]

I'm migrating from LaTeX to XeLaTeX on Debian Squeeze with TL2100. The
Arphic fonts are installed and work properly with LaTeX. But I'm having
trouble with XeLaTeX.

For example:

    \documentclass[12pt]{article}
    \usepackage{xltxtra}
    \setmainfont[Mapping=tex-text]{Linux Libertine O}
    \usepackage{xeCJK}
    \setCJKmainfont{AR PL KaitiM GB}
    \newfontfamily\sungtiGB{AR PL SungtiL GB}

    \begin{document}

        Main font: 无为

        Sung font: {\sungtiGB 无为}

    \end{document}

The chinese characters are all displayed om main font AR PL KaitiM GB
but the newfontfamily rather than the other fonts specified.

Haines Brown