can not set / change web.base.url

apparently this is set as default, but IMHO will rarely be the one useful in production envirenment

"web.base.url": lambda: "http://localhost:%s" % config.get('xmlrpc_port'),

IMHO it must be possilbe to change this value somewhere

this seems not to do it.
./openobject-server/openerp/addons/base/res/res_users.py

        if uid == openerp.SUPERUSER_ID:
            # Successfully logged in as admin!
            # Attempt to guess the web base url...
            if user_agent_env and user_agent_env.get('base_location'):
                cr = pooler.get_db(db).cursor()
                try:
                    self.pool.get('ir.config_parameter').set_param(cr, uid, 'web.base.url',
                                                                   user_agent_env['base_location'])
                    cr.commit()
                except Exception:
                    logging.getLogger('res.users').exception("Failed to update web.base.url configuration parameter")
                finally:
                    cr.close()