You don't have to use port 443 to tunnel. You simply open a connection to the proxy and use:
"CONNECT <remote host>:<any port> HTTP/1.0\r\n\r\n"

The proxy should answer (if he can connect) with
"some headers....\r\n
200 OK\r\n\r\n"

And then you are connected to the remote host through the proxy. It works for gnutella messages, uploads and downloads. Unfortunately not all http proxies support that.

__________________
Morgens ess ich Cornflakes und abends ess ich Brot
Und wenn ich lang genug gelebt hab, dann sterb ich und bin tot

--Fischmob