I've seen this problem in another thread (
http://shoutbox.menthix.net/showthread.php?tid=83737 ) ... Like I said there, I use a public VPN with OpenVPN to avoid every kind of firewall ( cause it passes from the https port, and it cannot be detected). But the certificate to authenticate with the public VPN costs a few bucks a month. If you want to try it send me a private message and I'll give you the address.
Cheers!!!