working with launchpad behind an authenticating proxy

[Denys Duchier]

at the university, my students must use a proxy for all http/https
connexions (however, I managed to put in place a forwarding gateway for
ssh connexions to launchpad.net).  the proxy is now "authenticating",
which means that they need to provide a username and password for ALL
connexions to the proxy.  since lp: urls need xmlrpc, some bzr commands
require them to enter username and password several times, and working
with bzr just becomes too bothersome.  To make things worse, their
username is their email address at university (yes, WITH an @ inside
which doesn't work with the <user>:<password>@<host>:<port> syntax).

Is there a way to configure the proxy username and password in
authentication.conf or something?

Cheers,

--Denys