I have been buying Creative Soundcards for around 10 years, if you cannot support your current soundcards for support with operating systems but one person can modify your drivers so their are no problems in Vista, I suggest that you recruit new software engineers capable of doing so because obviously the ones you have do not deserve to gave a job or maybe they are intentionally told not to make them fully compatable, either way you have brought down your own downfall.
Having read the Microsoft pages which show certified drivers in XP & Vista for a X-FI II, it just goes to show that Creative's only concern is giving campatability to future products & not what people use at present.
I for one will NOT be buying anymore products from Creative - EAX or no EAX I have past caring to be honest, I hope you go bankrupt / insolvent - would be better if your technology as well as that you have scavenged from putting other companys out of business be developed by other companys willing to give full support for soundcards.