I mean something like msahci in Vista. Something that works with every AHCI controller, even ones released years after the OS/driver. I know about UniATA, but unfortunately it only works with a select list of SATA controllers. It definitely does not work with the controller I want to use.
I don't intend to use it as a main OS, I just like fiddling around. Installing working XP on a modern system would be an achievement for me. I'd even try Windows 95, if I could.
I tried Win 98 to do something with old (very) hardware that had only W98 software/driver Had to give up in the end...
you have to download AHCI driver for specific chipset and integrate it in the Windows XP ISO image, otherwise better use Windows 7.