my $viewstate= get_viewstate( $ua ) or die "can't get viewstate field";
                                                                                
my $request=$ua->request(
  POST "https://www.saxobank.com/Default.aspx/?id=2&Lan=EN&Au=0&Grp=0",
  {
    __VIEWSTATE => $viewstate,
    txtUID      => 'me',
    txtPWD      => 'secret',
    submit      => 'log in'
  });
                                                                                
print $request->is_success ? $request->content : "failed\n";
                                                                                
# retrieve value for hidden __VIEWSTATE field (unique for each browser load?)
sub get_viewstate {
  my $ua= shift;
                                                                                
  require HTML::TokeParser;
  my $request= $ua->request(GET "http://www.saxobank.com/");
  die $request->status_line unless $request->is_success;
                                                                                
  my $p= HTML::TokeParser->new( \$request->content );
                                                                                
  while( my $tag= $p->get_tag("input") ) {
    return $tag->[1]{value} if $tag->[1]{name} eq '__VIEWSTATE';
  }
}