$VAR1 = {
          'parameters' => {
                            'requestDate' => '2011-05-13+02:00',
                            'vatNumber' => '1234567890',
                            'valid' => 0,
                            'countryCode' => 'IE'
                          }
        };

Request:
  POST http://ec.europa.eu/taxation_customs/vies/services/checkVatService HTTP/1.1
  User-Agent: libwww-perl/6.02
  Content-Length: 347
  Content-Type: text/xml; charset="utf-8"
  SOAPAction: ""
  X-LWP-Version: 6.02
  X-XML-Compile-Cache-Version: 0.991
  X-XML-Compile-SOAP-Version: 2.23
  X-XML-Compile-Version: 1.21
  X-XML-LibXML-Version: 1.70

  <?xml version="1.0" encoding="UTF-8"?>
  <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"><SOAP-ENV:Body><tns1:checkVat xmlns:tns1="urn:ec.europa.eu:taxud:vies:services:checkVat:types"><tns1:countryCode>IE</tns1:countryCode><tns1:vatNumber>1234567890</tns1:vatNumber></tns1:checkVat></SOAP-ENV:Body></SOAP-ENV:Envelope>

Response:
  HTTP/1.1 200 OK
  Connection: Keep-Alive
  Date: Fri, 13 May 2011 08:01:45 GMT
  Content-Type: text/xml; charset=utf-8
  Client-Date: Fri, 13 May 2011 08:01:53 GMT
  Client-Peer: 147.67.119.103:80
  Client-Response-Num: 1
  Client-Transfer-Encoding: chunked

  <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body><urn:checkVatResponse xmlns:urn="urn:ec.europa.eu:taxud:vies:services:checkVat:types"><urn:countryCode>IE</urn:countryCode><urn:vatNumber>1234567890</urn:vatNumber><urn:requestDate>2011-05-13+02:00</urn:requestDate><urn:valid>false</urn:valid></urn:checkVatResponse></soapenv:Body></soapenv:Envelope>