The EWI manual seems to suggest that using it on a USB hub is likely to cause problems. It doesn't say don't - it just says that ARIA might not see the EWI.
So I just thought I'd ask whether any is doing it successfully. My computers are hidden quite a long way under the desk, and I need to go around on my hands and knees to plug the EWI in. Then I have to sit really close to the desk to play it. It would be so much easier if I could put a hub on top of the desk and plug into that.