Vista x64 dual boot WinXP with RAID-5 ICH8R messes up RAID array

I have a new pc (2 months old) with Windows XP and 3 500GB discs in RAID-5
(total of 950GByte available). I'm using the on-board Intel ICH8R chip with
Intel drivers.
Now I tried to install Vista x64 on a seperate partition of 100GByte (on the
RAID-5).

I thought this new shiny Vista DVD would have all the drivers needed for the
latest and finest hardware. So I just started the PC from DVD. Vista install
starts and after a few clicks shows the 'available volumes'. The existing
RAID-5 array is mentioned as '950GByte Unallocated space'. PANIC, my Windows
XP is in the first 850GByte, it's not unallocated.
There is a button to install a driver (from floppy !!!), but I dont have
that driver so I decide to reboot in WinXP.

BIG PANIC, the pc doesnt reboot. The RAID-5 array is corrupt. It seems Vista
has written something to one of the disc (only one, LESS PANIC). The
BIOS/WinXP system needs some manual help and then starts rebuilding the
RAID-5 array. A 24-hour mission.

Why did Vista write something to this disc? It almost destroyed my WinXP
setup.

I dont trust it anymore, no Vista for me anymore until someone has
thoroughly tested this.

Oh yes, the RC2 I also tried, this did not even boot, some driver error. But
it did not mess up the raid array.

Any suggestions?