Hi Deepak,
Enterprise wsdl can be used, basically you have to first call the Login method using a SOAP Lookup and pass the user/ password and in return get the server URL and session id. Then do further Upsert/ Update using a normal SOAP call and in that soap call pass the session id in soap header.
Closing this thread as got the solution, you can implement SALESFORCE integration using Enterpise esdl, REST API, BULK API etc.
Regards
RJ