You use the OSD's assistant, I was scratching my head a first as well. Go into data view mode, but don't bother using the GPS Exporter to load from the OSD (OSD's assistant in view mode makes the osd basically a external disk). You'll see the OSD as a drive on your computer, just copy your dat files to you HD. Then load the dat from you HD with the GPS exporter. Be warned, there's no time stamp though... Pretty hard to sync you photos without it.
You can download the iOSD Assistant Software from the DJI product page:
http://www.dji-innovations.com/download/iosd-mark-ii-downloads/