How to set privacy settings while posting on a facebook feed, using FB.ui()

I would like to submit a post to Facebook that will be visible to a specific list of friends only. I know that it is possible to set a privacy property for that, as specified on Facebook's Graph API, but I need to use the FB.ui() so that the user can preview the post and update its message.

That's the code I use:

    FB.ui({
            method: 'feed',
            message: text,
            name: name,
            link: link,
            picture: picture,
            caption: text,
            description: description,
            privacy: {value: "CUSTOM", friends: "SOME_FR开发者_StackOverflow中文版IENDS", allow:"666666"}
        }
    );

This code works but the privacy property seems to be ignored, as my default privacy settings are applied to this post...

Is there a way to set this privacy property from the FB.ui() function?

When using the FB.ui, the user has the option to set the privacy settings on their own (the lock in the bottom of the window) and so Facebook does not allow you to override the users default privacy option.