code: public boolean sms_canSend(Integer userId)
      throws FacebookException, IOException {
      return extractBoolean(this.callMethod(FacebookMethod.SMS_CAN_SEND,
                                            new Pair<String, CharSequence>("uid",
                                                                           userId.toString())));
    }
docs: Determines whether this application can send SMS to the user identified by <code>userId</code>
  @param userId a user ID
  @return true if sms can be sent to the user
  @see FacebookExtendedPerm#SMS
  @see <a href="http://wiki.developers.facebook.com/index.php/Mobile#Application_generated_messages">
  Developers Wiki: Mobile: Application Generated Messages</a>