Missing proxyAuthenticationNeeded signal for NTLM

I have a very simple test application that shows a missing authentication attempt to an NTLM based Exchange server. I have tested that on some servers this does signal authMissing. On others it doesn't. I have the name of a test server, in case it's needed. Please ask me on bthorsen at ics dot com for the hostname.

#include <QCoreApplication>
#include <QNetworkAccessManager>
#include <QNetworkReply>

class Connect : public QObject {
Q_OBJECT
public slots:
void authRequired()

{ qDebug("auth required"); }

void proxyAuthRequired()

{ qDebug("proxy auth required"); }

void sslErrors()

{ qDebug("ssl errors"); }

void finished()

{ qDebug("finished"); }

};

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QNetworkAccessManager qnam;
Connect c;
QObject::connect(&qnam, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)), &c, SLOT(authRequired()));
QObject::connect(&qnam, SIGNAL(proxyAuthenticationRequired(QNetworkProxy,QAuthenticator*)), &c, SLOT(proxyAuthRequired()));
QObject::connect(&qnam, SIGNAL(sslErrors(QNetworkReply*,QList<QSslError>)), &c, SLOT(sslErrors()));
QObject::connect(&qnam, SIGNAL(finished(QNetworkReply*)), &c, SLOT(finished()));
QNetworkRequest request(QUrl("https://mail.prokom.dk/EWS/Exchange.asmx"));
request.setHeader(QNetworkRequest::ContentTypeHeader, "text/xml; charset=utf-8");
qnam.post(request, QByteArray());
return a.exec();
}

#include "main.moc"