As I've mentioned (perhaps not very clearly) in my first post, check out post #12:
Windows XP - Installing to SATA _WITHOUT_ a Floppy Disk
This is using nLite which allows you to do all sorts of funky things very easily and is perfect for slipstreaming. Whatever controller you have, you should go to your motherboard/controller card's manufacturer's website and download their latest drivers. You should then be able to use those in conjunction with nLite in order to make your slipstreamed XP CD.
Good luck!