SSL pages don't work when loaded with a proxy

I'm trying to connect to Linkedin (ssl) with a proxy, but despite the connection working on chrome with the same details, it fails to load even an error page on curl. This is the code I'm using:
$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, 'https://www.linkedin.com/reg/join');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_PROXY, '217.196.235.20:80');
curl_setopt($ch, CURLOPT_PROXYPORT, 80);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$contents = curl_exec($ch);
print $contents;
curl_close($ch);
Thanks

_______________________________________________
http://cool.haxx.se/cgi-bin/mailman/listinfo/curl-and-php