protected $user = "********";
protected $password = "********";
protected $organisation = "********";
protected $administration = "********";

protected $header = NULL;

protected $data = false;

private function getSession() {
$ret = false;

$params = array( 'user' => $this->user,
'password' => $this->password,
'organisation' => $this->organisation
);

$cache = Zend_Registry::get ( 'Cache' );

if( $this->data === false && ( $this->data = $cache->load( md5("Twinfield_Session_And_Url") ) ) === false ) {
$client = new Zend_Soap_Client( "https://login.twinfield.com/webservices/session.asmx?wsdl" );

$client->logon( $params );

$doc = new domDocument();
$doc->loadXML( $client->getLastResponse() );

$this->data['SessionID'] = $doc->getElementsByTagName('SessionID')->item(0)->textContent;
$cluster = $doc->getElementsByTagName('cluster')->item(0)->textContent;
$this->data['cluster'] = $cluster . '/webservices/processxml.asmx?wsdl';

$client = new Zend_Soap_Client( $cluster . '/webservices/session.asmx?wsdl' );
$header = new SoapHeader( 'http://www.twinfield.com/', 'Header', array( 'SessionID' => $this->data['SessionID'] ) );
$client->addSoapInputHeader( $header );
$client->SelectCompany( array( 'company' => $this->administration ) );

$doc = new domDocument();
$doc->loadXML( $client->getLastResponse() );
$result = $doc->getElementsByTagName('SelectCompanyResult')->item(0)->textContent;

# Alleen het resultaat bewaren als alles goed gegaan is
if( strcmp( $result, "Ok" ) ) {
$cache->save( $this->data );
$ret = true;
}
}

return $ret;
}

public function __construct( ) {
if( $this->getSession() ) {
parent::__construct( $this->data['cluster'] );

$this->header = new SoapHeader( 'http://www.twinfield.com/', 'Header', array( 'SessionID' => $this->data['SessionID'] ) );