Has anyone here tried using an IR extender plugged into the IR jack on the back of a Cox leased 8240HDC, 8642HDC, 8742HDC, 8752HDC, or 9865HDC DVRs? If so, what device and which DVR? Cox claims that this function has been turned off by the firmware. Cisco claims that it is not possible for firmware to disable this function. Any real life examples?