Webkit + Proxy problem

[giusepped]

I implemented a simple interface to connect to Google Map API.
The connection starts by creating

manager = new QNetworkAccessManager(this);
 
	this->page()->mainFrame()->addToJavaScriptWindowObject("Map", this);
 
 
	connect(this,SIGNAL(urlChanged(const QUrl&)),SLOT(waitPage()));
        connect(page()->mainFrame(), SIGNAL(javaScriptWindowObjectCleared()),
            this, SLOT(populateJavaScriptWindowObject()));
 
	connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(replyFinished(QNetworkReply*)));
	connect(this,SIGNAL(reloadMap()), this,SLOT(loadCoordinates()));

manager = new QNetworkAccessManager(this);

	this->page()->mainFrame()->addToJavaScriptWindowObject("Map", this);
	
 
	connect(this,SIGNAL(urlChanged(const QUrl&)),SLOT(waitPage()));
        connect(page()->mainFrame(), SIGNAL(javaScriptWindowObjectCleared()),
            this, SLOT(populateJavaScriptWindowObject()));

	connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(replyFinished(QNetworkReply*)));
	connect(this,SIGNAL(reloadMap()), this,SLOT(loadCoordinates()));

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The code works fine, but some users said to me that they could not connect and the map does not show at all.
I guess that some of them use Proxy to connect to Internet.Shall I implement a Proxy also in QNetworkAccessManager?
regards