This is called a wrapper class. Every wrapper class corresponds to a SOAP message that you can see in your WSDL. So if your service has three methods you have six wrapper classes, two for each method (request/response). Your parameters are wihtin the wrapper class as JAXBElement's and accessible with getter/setter. To create JAXBElements you can use Object factories created by wsimport. To get parameter value from a JAXBElement use for example:
String name = jaxbElement.getValue();
Take care about implicit SOAP headers, e.g. CallContext. To get CallContext in your method signature
@WebParam(name = "CallContext", targetNamespace = schemas.microsoft.com/.../datacontracts", header = true, partName = "context") CallContext context)
you have to use wsimport with option -XadditionalHeaders.