XML Parser EXPAT DBCS encoding error

Dear All,
        I follow Club Tech iSeries Programming Tips -- March 17,
2005(publiched by Scott Klement) to do XML string parsing, but when I change
the contents encoding 

<?xml version="1.0" encoding="Big5?> and also set sample RPGLE as following

D encoding        s              5A   Inz('Big5')

encoding = encoding + X'00';
p = XML_ParserCreate(%addr(encoding));

When I run it, I got "Parse error at line 1, unknown encoding" error
message, I also do another test, set XML back 

<?xml version="1.0"?>
And change <name> tag to <name>XXXX</name> , which XXXX means 2 DBCS big5
chars.
RPG use :
p = XML_ParserCreate(*NULL);

And got "Parse error at line 4: not well-formed (invalid token)" ,

How do I set the encoding support DBCS ?

Best regards,

Vengoal