Posting on User's friend's wall with Facebook

Is there any way to post somet开发者_开发知识库hing to a user's friend's wall from that user in my facebook app?

Example: A user of my facebook app answers a question about one of his friends. I want a small message to be posted to the wall of that friend saying 'Bob answered a question about you...'

Is that possible? If so, how?

It seems that this is possible, the following code is working:

 $result = $facebook->api('/$friendsUserId/feed', 'POST', array(                
            'name'    => 'TEST NAME',
            'caption' => 'Test Caption',
            'description' => 'Test Description',
            'message' => 'this is a test.',
        ));
    print_r($result);
    die;