SOAPCall

[faultyzone]

Hello
im dealing with a thunderbird add-on. this add-on can search or create
strings at server side.
im trying to use multibyte strings especially japanese. server side
only accepting UTF-8 encoding.
the problem is that when i create strings from addon i can search them
from add-on perfectly.
but when i create strings at server side i cannot search them from
addon.
add-on is using single SOAPCall for both searching and creating
process like this:

...
var sCall = new SOAPCall();
sCall.transportURI = wsdl_uri.substring(0,wsdl_uri.indexOf
("?"));
sCall.encode(0, method, "http://www.......", 0, null,
params.length, params);

var returnObject = sCall.invoke();
...

is this SOAPCall.encode() method support UTF-8 conversion or is the
parameter sent to server with its original encoding?

any idea?
thanks for any help