All you can do to see if the iPad will recognize that USB stick is to plug it in to the Camera Connection Kit (CCK) adapter and then plug it into the iPad.
Once you've plugged it in, open iFile. If ifile recognizes the USB stick, you're in business. If it doesn't, then there is nothing moryou can do cause that USB won't be recognized by anything else. Apple changed the power requirements/output of the 30-pin connected, so if a USB stick works - it's quite rare. The best chance is to use an SD/SDHC card.
Hope some of this helps. Holler back if I've wandered too far away from your question...