Facebook App - Publish to friends News Feed

Question

I'm in the middle of building a Facebook App, I want the app to publish a predefined message to:

1) A user's news feed ( i.e. any user who has used the app )

2) If possible to the user's friend's news feeds or even their wall.

At the moment, I only have it posting to a user's wall, using the following code:

if(isset($_POST['mapp_message'])){
        try {
            $facebook->api('/me/feed', 'POST', array(
                'access_token' => $facebook->getAccessToken(),              
                'message' => $_POST['mapp_message'],
                'name' => "This is the title of my post",
                'description' => "This is the body of the post with lots of text in it",
                'link' => 'http://www.mysite.com',
                'picture'=>"http://lipsum.com/images/lipsum07.gif",
                'privacy' => array('value' => 'EVERYONE')               
            ));
            $sent = true;
        } catch (FacebookApiException $e) {
            //do something about it
        }
    }

Note: I've just discovered that their is a difference between the users wall and news feed.

I've been googling this for a few hours, but I haven't been able to figure it out. So any help appreciated.

Regards

UPDATE

Ok, I made a bit of progress. I managed to get it posting on user's friend's walls ( i.e. friends of people who have used the app ). The code is as follows:

try {
        $userData = $facebook->api('/me');

    } catch (FacebookApiException $e) {
        //do something about it
    }    

try {
            $friendsTmp = $facebook->api('/' . $userData['id'] . '/friends');
            shuffle($friendsTmp['data']);
            array_splice($friendsTmp['data'], 5);
            $friends = $friendsTmp['data'];
        } catch (FacebookApiException $e) {
            //do something about it
        }

This bit of code randomly selects 5 friends of the user who has used the app and to post to their walls the code is as follows:

foreach($friends as $k => $i){                                      
                $facebook->api('/'.$i['id'].'/feed', 'POST', array(
                    'access_token' => $facebook->getAccessToken(),              
                    'message' => $_POST['mapp_message'],
                    'name' => "This is the title of my post",
                    'description' => "This is the body of the post with lots of text in it",
                    'link' => 'http://www.mysite.com',
                    'picture'=>"http://lipsum.com/images/lipsum07.gif"
                    //'privacy' => array('value' => 'EVERYONE')             
                ));                                     
            }

But I still would prefer if I could get this posted to the News Feeds instead.