Post on friend's wall using PHP SDK 3.0

Question

I have a friend, Bob, which allowed my app for tests. The app has publish_stream perms.

publish_stream desc :

Enables your app to post content, comments, and likes to a user's stream and to the streams of the user's friends. With this permission, you can publish content to a user's feed at any time, without requiring offline_access.

Means that I, the owner of the app, can post content on the stream of Bob's friends, at any time, even if Bob is offline.

I have Bob's ID : 111 I have Bob's best friend, Ben, ID : 222

Ben has now allowed my app for use.

How can I post content on Ben's stream on the behalf of Bob, while Bob is offline ?