web service authentication using php

POST /xxxx/service.asmx HTTP/1.1
Host: xxx.xxx.xxx.xx
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://ift.tt/1NoYcb7"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://ift.tt/ra1lAU" xmlns:xsd="http://ift.tt/tphNwY" xmlns:soap="http://ift.tt/sVJIaE">
  <soap:Body>
    <GetLogin xmlns="http://nhiapps.org/">
      <username>string</username>
      <password>string</password>
      <AppsID>string</AppsID>
    </GetLogin>
  </soap:Body>
</soap:Envelope>

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://ift.tt/ra1lAU" xmlns:xsd="http://ift.tt/tphNwY" xmlns:soap="http://ift.tt/sVJIaE">
  <soap:Body>
    <GetLoginResponse xmlns="http://nhiapps.org/">
      <GetLoginResult>string</GetLoginResult>
    </GetLoginResponse>
  </soap:Body>
</soap:Envelope>

This is my SOAP code . I want to perform web service authentication using php, i have to call the get login function present in the ip address for authentication completion Please Help