How to change privacy settings of a feed post?

Hi,

I want to send a post to another user timeline and make it visible only to this user.

I’ve tried:

facebook.request(username .. "/feed", "POST", {message = msg, link = "http://google.com", privacy = "{'value':'SELF'}"})

as well as:

facebook.request(username .. "/feed", "POST", {message = msg, link = "http://cluain.pl/defender", to = username, privacy = {value = 'SELF'}})

But the first example posted message to all of the friends of <username> and the other one would throw a NSDictionary error.

Is there any way I could set the privacy settings?