My guess is that you will need to use some other PC or Mac other than your Pocket PC. Get the files to that computer, and then place them on the iPod in disk mode by simply dragging them on.
I havnt been up to date on Pocket PC's for a few years, but back then you couldn't do it. and i doubt that now, with Pocket PCs with USB i doubt that they have the drivers to recognize the iPod.