Hi Mr mbsolution..
actually i think i found a way to do just what i need.. using shortcodes from the plugin..
[si-contact-form form='1' hidden='key=value']
but you have to enable php sessions settings on the form you are using and since the shortcode is being included on my theme file i can manipulate what value i want to put for the hidden input field..
for example
<?php
$my_shortcode = '[si-contact-form form=\'2\' hidden=\'pagetitle=' . get_the_title(). '\']';
?>
<?php echo do_shortcode($my_shortcode); ?>
still working on it though..
thanks a lot sir for the heads up..