If Vista recognizes your RAID array it will install just like it owuld on a normal drive.
As far as the driver support it will be lower with a 64 Bit system since there is less driver support for that than a 32 bit system in the first place.
But overall the driver support from developers and manufactorers is less than satisfactory. It is still very sub-par. Which is a big dis-appointment since Vista has been out for almost 2 months already.