Connecting to google talk through pidgin on awkward network

[PhiJ]

I've just (well a month ago) moved to a new university, living in halls, and can't connect to google talk via pidgin. Works fine in firefox.

All http(s) must go through a proxy on the network, but not e.g. telnet or rsync.

I've tried a direct connection to google talk (using the standard options), and it tells me I'm logged on, shows me which friends are logged on, times out (I think), and when you try to reconnect it looks like it's successful, but it says everybody is offline. Looking at google talk in the browser demonstrates that this is false. Lots of people are online.

I've tried various http proxy settings which should work, but they get me this error "Unable to find alternative XMPP connection methods after failing to connect directly."

I've tried calling up the helpline, and after an initial 'we don't support linux or google' we tried a few different proxy settings, and they mostly got the same error message. One got an 'invalid proxy address' style message.

Any ideas?