problem with php nusoap connecting .net web service

hi, i got a problem when i'm trying to connect to a .net web service through php.

actually the problem is:
Server did not recognize the value of HTTP Header SOAPAction:

first i didnt define any value for soapaction, after i found i must do, i pass the variable, it take it ok, but it still the same problem. i dont know which value i must pass throgh this variable, if someon can help me. i leave you here the code i use:

<?
require_once('soap/lib/nusoap.php');

$example = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>
<datarefresh source=\"city\" clientid=\"CLIENTID\" user=\"USERNAME\" pass=\"PASSWORD\">
<clientid>227867</clientid>
<select name=\"Buenos Aires\" country=\"AR\"></select>
</datarefresh>";

//$soapaction = "http://xml.dev.hoteldo.com/Datarefresh";
$soapaction = "http://xml.dev.hoteldo.com/send";

$wsdl = "http://xml.dev.hoteldo.com/HoteldoInterface.asmx?WSDL";
$client = new nusoap_client($wsdl, true);

$result = $client->send($example, $soapaction);

if ($client->fault) {
echo '<h2>Fault</h2><pre>'; print_r($result); echo '</pre>';
} else {
$err = $client->getError();
if ($err) {
echo '<h2>Error</h2><pre>' . $err . '</pre>';
} else {
echo '<h2>Result</h2><pre>'; print_r($result); echo '</pre>';
}
}

echo '<h2>Request</h2><pre>' . htmlspecialchars($client->request, ENT_QUOTES) . '</pre>';
echo '<h2>Response</h2><pre>' . htmlspecialchars($client->response, ENT_QUOTES) . '</pre>';
echo '<h2>Debug</h2><pre>' . htmlspecialchars($client->debug_str, ENT_QUOTES) . '</pre>';
?>

 

Can you read WSDL file for the service? That way you'll know what arguments the service needs/what it'll returns.

I remember you can let nusoap read the WSDL and then you can pass the required arguments into send() function as array, not 100% sure about this though it's been a long time.