launchpad plugin xmlrpc does not use $http_proxy (branching lp: uris does not use system http proxy)

In my company network we have to use http proxy, else http connections just timeout. bzr branch lp:something does not use $http_proxy and so it times out.

gjc@spectrum:tmp$ bzr branch lp:pybindgen
bzr: ERROR: socket.error: (110, 'Connection timed out')

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 802, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 758, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 877, in run
    br_from = Branch.open(from_location)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 128, in open
    possible_transports=possible_transports)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 572, in open
    return BzrDir.open_from_transport(t, _unsupported=_unsupported)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 609, in open_from_transport
    redirected)
  File "/usr/lib/python2.5/site-packages/bzrlib/lazy_import.py", line 125, in __call__
    return obj(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/transport/__init__.py", line 1661, in do_catching_redirections
    return action(transport)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 586, in find_format
    transport, _server_formats=_server_formats)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 1307, in find_format
    return format.probe_transport(transport)
  File "/usr/lib/python2.5/site-packages/bzrlib/bzrdir.py", line 1317, in probe_transport
    format_string = transport.get(".bzr/branch-format").read()
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad/lp_indirect.py", line 137, in get
    self._request_redirect(relpath)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad/lp_indirect.py", line 130, in _request_redirect
    target = self._resolve(branchpath) + extra
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad/lp_indirect.py", line 85, in _resolve
    result = resolve.submit(service)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad/lp_registration.py", line 155, in submit
    self._authenticated)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad/lp_registration.py", line 120, in send_request
    result = method(*method_params)
  File "xmlrpclib.py", line 1147, in __call__
    return self.__send(self.__name, args)
  File "xmlrpclib.py", line 1437, in __request
    verbose=self.__verbose
  File "xmlrpclib.py", line 1183, in request
    self.send_content(h, request_body)
  File "xmlrpclib.py", line 1297, in send_content
    connection.endheaders()
  File "httplib.py", line 856, in endheaders
    self._send_output()
  File "httplib.py", line 728, in _send_output
    self.send(msg)
  File "httplib.py", line 695, in send
    self.connect()
  File "httplib.py", line 1130, in connect
    sock.connect((self.host, self.port))
  File "<string>", line 1, in connect
error: (110, 'Connection timed out')

bzr 1.0.0 on python 2.5.1.final.0 (linux2)
arguments: ['/usr/bin/bzr', 'branch', 'lp:pybindgen']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  gnulog /home/gjc/.bazaar/plugins/gnulog.pyc [unknown]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
  multiparent /usr/lib/python2.5/site-packages/bzrlib/plugins/multiparent.pyc [unknown]
  signing /home/gjc/.bazaar/plugins/signing [unknown]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.

But normal bzr works fine with proxy:

gjc@spectrum:tmp$ bzr branch http://bazaar.launchpad.net/~gjc/pybindgen/trunk
Branched 329 revision(s).