FTP over HTTP Proxy not working

As per Qt documentation 4.8

QFtp does not support FTP-over-HTTP proxy servers. Use QNetworkAccessManager for this.

But it doesn’t work with QNetworkAccessManager either. I am behind a Squid HTTP proxy server and ftp downloads work fine with all the browsers, and UGET also, but it fails with QNetworkAccessManager, with the

error: no suitable proxy found

QUrl url("ftp://rpmfind.net/linux/epel/testing/6/ppc64/wicd-1.7.0-4.el6.ppc64.rpm");
QNetworkReply* reply;
request.setUrl(url);
proxy.setHostName(host);
proxy.setPort(port_num);
proxy.setType(QNetworkProxy::HttpProxy);
manager.setProxy(proxy);
reply=manager.get(request);
connect(&manager, SIGNAL(finished(QNetworkReply*)),this,
SLOT(finished(QNetworkReply*)));