How to export video on XVR VT-SC3?

Hi, i have an VT-SC3 XVR system.
From the internet explorer web interface (as watchtower pc software doesn’t work!!!) i want to export one video. I go to “playback”, I put the time of the day i want export , i click “search” then i go “Recording” and export. I see the progress bar going on but at the end i can’t find how to save on my pc. I put an usb key formatted in fat32 and i did it again but nothing.