how to pass the parameters in the browser to retrieve the webservice value

I know we can retrieve the value passing the parameters thru browser and get the value.
i have webservice ,am trying to valid against browser,i need to pass these value to return the vlaue
string LoginName, string Password, System.Nullable<System.DateTime> LastExport, out string ErrorMessage)
How to pass the value in the browser,any help ?
consider my webservice wsdl file
eg: http://localhost:63938/Service1.asmx