I have a CVP, so my screen may look a little different, but look on page 32 of your Genos user manual. Shows the voice section screen, and at the top middle is an icon showing the usb and user voice select. If you have a usb plugged in you should see this. If you do but when you select it the usb shows no files, then there may be something wrong with either file format or the usb format.
If you still have issues load a style in the same usb, try this on the style selection screen. If you can see the usb, and can select the style there is not a problem with the usb. Problem would have to be with the voice file.
Mike