I found that I could get it working in WoW with IS, so that IS would recognise it (as Ugh's image shows) but a problem I still have is that when I click (one of the middle mouse buttons) in one WoW instance, the mouse software (not IS) would make the click happen on all the WoW instances. Not sure whether my configuration is wrong, I ended up living with it, but I'll get around to trying to sort it out one day...