SOAP Fault: Security requirements are not satisfied because the security header is not present in the incoming message

Question

I am trying to integrate salesforce with exacttarget using the SOAP wsdl provided by Exacttarget.

I am able to generate apex classes , but on calling the create request , I get the error System.CalloutException: Web service callout failed.

Since I am new to apex , I am not sure if SOAP header request can be done only through http ? or can I do it through my class.

Please find below the code I am using.

exacttargetComWsdlPartnerapi.Soap soapReq = new exacttargetComWsdlPartnerapi.Soap();
exacttargetComWsdlPartnerapi.UsernameAuthentication authentication = new exacttargetComWsdlPartnerapi.UsernameAuthentication();
authentication.UserName = '******'; 
authentication.PassWord = '*****';
soapReq.inputHttpHeaders_x = new Map<String, String>();
soapReq.outputHttpHeaders_x = new Map<String, String>();
//String myData = '[email protected]:smruti@123';
//authentication = EncodingUtil.base64Encode(Blob.valueOf(myData));
soapReq.inputHttpHeaders_x.put('Authorization','Basic ' + authentication );SALESFORCE STUB
exacttargetComWsdlPartnerapi.CreateOptions optList = new exacttargetComWsdlPartnerapi.CreateOptions();
exacttargetComWsdlPartnerapi.ContainerID contnr = new exacttargetComWsdlPartnerapi.ContainerID();
exacttargetComWsdlPartnerapi.APIObject apiObj = new exacttargetComWsdlPartnerapi.APIObject();
exacttargetComWsdlPartnerapi.APIProperty apiProp = new exacttargetComWsdlPartnerapi.APIProperty();
List<exacttargetComWsdlPartnerapi.APIProperty> propList = new List<exacttargetComWsdlPartnerapi.APIProperty>();
apiProp.Name='EmailAddress';
apiprop.Value='[email protected]';
propList.add(apiProp);
apiObj.PartnerProperties=propList;
contnr.APIObject = apiObj;
optList.Container = contnr;
List<exacttargetComWsdlPartnerapi.APIObject> objList = new List<exacttargetComWsdlPartnerapi.APIObject>();
objList.add(apiObj);
exacttargetComWsdlPartnerapi.CreateResponse_element response = soapReq.Create(optList,objList);
System.debug('** Result ==>' + response);