[Q] Get "Access Denied" when accessing external SD Card via Wireless Storage topic

Am trying to use LG's Wireless Storage function to copy files to the external SD Card from Windows 7 (IE11). Whereas it works fine with the internal memory (sdcard0), but I have only write access to the external SD card. It seems I can only write to it via the USB cable. Any idea why this may be, and more importantly how to fix it? Also why is it all so slow??