Custom Subject for Notifications « Gravity Support Forums

Hi,

I am creating a "Tell a friend" type form, and in the form the user can optionally specify the subject of the email.

When I come to send the notification out, what I would like to do, is use that subject if it is not empty otherwise use a default subject line.

Following from the info I found in this forum post: http://forum.gravityhelp.com/topic/in-replace_variables-what-is I came up with the code below however it doesn't work.

Added to functions.php:

add_filter("gform_pre_submission_filter", "editfields");

function editfields($form){
    // only action on the sendtofriend form id=1
    if($form["id"] != 1) {
        return;
	}

	// Set the subject line to the users if they entered one, else set to default
	if (trim($_POST["input_10"]) != "") {
		$subject = trim($_POST["input_10"]);
	} else {
		$subject = 'hopkinsrealty.com.au - property from a friend';
	}

    $form["notification"]["subject"] = $subject;
    return $form;
}

Thanks any help would be appreciated!