I am using SoapUI and my request looks like : <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:amex="http://domain/path/"> <soapenv:Header> <Security> ...
I believe that when request is send using soapui, it might be sending MustUnderstand with value 1, but not 0. So, how did you manage to send the request with MustUnderstand=0?