isSessionValid() is true but inet disconnected (prime31)

hello,

i have a problem including facebook stuff in a game app. i use prime31's social networking plugin (for ios and android). the problem is - i check if isSessionValid is true to show posting options. when facebook-status is "logged in" in the app, isSessionValid returns true and the options are shown. but if i then disconnect the internet on my phone, isSessionValid still returns true when checking. this allows the player to make facebook posts (to get stuff ingame) without the facebook posts actually made and could lead to unwanted abuse. i dont know how to let the plugin "re-check" if facebook posting is actually possible at all at the moment. any hints? thanks, m.