Can't override mail sender and subject via drupal_mail

I'm trying to send custom email via rules php but they are sent with the default email and with no object.

I use this code:
drupal_mail($module, $key, $to, $language, $params, $from, $send);

The $params array is this:
$params = array(
'subject' => 'My Custom Object'
);

The $from variable is "myemail@address.com"

How can I alter the default mail sender and subject?