my ($username, $password) = $ua->get_basic_credentials("Support");
# This code is culled from XML::Atom::Client::munge_request().
my $nonce = XML::Atom::Client::make_nonce();                               
my $nonce_enc = encode_base64($nonce, '');                                 
my $now = DateTime->now->iso8601 . 'Z';                                    
my $digest = encode_base64(sha1($nonce . $now . ($password || '')), '');
$ua->default_header('WWW-Authenticate', 'WSSE realm="Support", profile="UsernameToken"');                                                                 
$ua->default_header('Authorization', 'WSSE profile="UsernameToken"');
$ua->default_header('X-WSSE', sprintf                                      
                 qq(UsernameToken Username="%s", PasswordDigest="%s", Nonce="%s", Created="%s"),                                                          
             $username || '', $digest, $nonce_enc, $now);