[xml] xpath containing Chinese

[<lxl0621 vip sina com>]

I use a Chinese xml file containing Chinese dtd file when I signature .
For example,it is book.dtd: 
 <!ELEMENT books (#PCDATA|Ãû×Ö|writer> 
 <!ELEMENT Ãû×Ö (#PCDATA)> 
 <!ELEMENT writer (#PCDATA)> 

Now I signature the whole xml file .Signature is OK.
But when I signture using "#xpointer(id('Ãû×Ö'))" or "ancestor-or-self::Ãû×Ö" ,signature failed. While I use 
"Name" instead of "Ãû×Ö" in the xml file and dtd file ,the signature is OK.

Can you tell me where is the problem ? In xmlsec or in libxml2 ?
I use xmllint bookxml xpath "ancestor-or-self::Ãû×Ö" in libxml2 and find xpath error Encoding error .I 
considered the problem is from libxml2 .Can you give me the answer ?
Thank you .


______________________________________

===================================================================