webservice传入自定义参数问题

POST /CarRequest.asmx HTTP/1.1
Host: 202.102.112.25
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://202.102.112.25/GetCarLastTrack"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
  <GetCarLastTrack xmlns="http://202.102.112.25/">
  <user>
  <companyName>string</companyName>
  <userName>string</userName>
  <password>string</password>
  </user>
  <carId>string</carId>
  </GetCarLastTrack>
  </soap:Body>
</soap:Envelope>


如上所示，在调用是，user的参数如何传入，谢谢。

用的什么访问？