how to add Fault message tag in webservice not in WCF?

hi all ,
i want to write fault message tag when ever i see the WSDL file. i have developed the Web service.
       <fault message='tns:ExceptionDemo' name='ExceptionDemo'></fault>
how can i acheive above one.
if i use WCF it will come by Faul contract.here i used the webservices.
for that what i need to write.
i searched in google ,all are saying that its not possible to acheive it.
but very few people said it can be done by using Webservice.
 
please tell me the correct solution
if i add
<?xml version='1.0' encoding='UTF-8'?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" xmlns:xsd="http://www.w3.org/1999/XMLSchema"> <SOAP-ENV:Body> <SOAP-ENV:Fault> <faultcode xsi:type="xsd:string"> ...