[Cjk] \CJKnumber and bookmarksnumbered option of hyperref

[ysx_zh at sina.com]

Hi there,

I hope to use \CJKnumber to get Chinese numbered chapter, and I get what I need. 
However, the bookmarks is something strange, if I use bookmarksnumbered option of hyperref.

If the encoding changed to UTF8, a more error massage appeared:

Chapter \CJKnumber {1}.
! Missing \endcsname inserted.
<to be read again>
                   \CJK at tempa
l.9   \chapter{test}

?


Any suggestions? Thanks!

Regards,
Jinsong

%%%%%%%%%% source code %%%%%%%%%%%%%

\documentclass{book}
\usepackage{CJK,CJKnumb}
\usepackage[CJKbookmarks,bookmarksnumbered]{hyperref}
\begin{document}
\begin{CJK}{GB}{gbsn}
  \makeatletter
  \renewcommand\thechapter{\CJKnumber{\@arabic\c at chapter}}
  \makeatother
  \chapter{test}
\end{CJK}
\end{document}

The related log message is following:

Package hyperref Warning: Token not allowed in a PDFDocEncoded string,
(hyperref)                removing `\let' on input line 9.


Package hyperref Warning: Token not allowed in a PDFDocEncoded string,
(hyperref)                removing `\CJK at q' on input line 9.


Package hyperref Warning: Token not allowed in a PDFDocEncoded string,
(hyperref)                removing `\let' on input line 9.


Package hyperref Warning: Token not allowed in a PDFDocEncoded string,
(hyperref)                removing `\let' on input line 9.


Package hyperref Warning: Token not allowed in a PDFDocEncoded string,
(hyperref)                removing `\CJKchar ' on input line 9.