Zend certified PHP/Magento developer

Mount SFTP server reachable via HTTP proxy as a windows local drive

I need to mount SFTP server path as local drive in Windows Server with user credential. The problem is that the server is reachable only by HTTP proxy on port 80 without any authorization on proxy. How to configure that? Do I need some external software?

I did a research but withou any answers for http proxy server.