My... you're just asking for disaster, aren't you?
(Two partitions with 2 separate OSes on a RAID 0 array... yikes!)
Well, first, you're going to need a driver for your RAID controller in XP. You have to load it when it prompts you to press F6 to load additional drivers. This will require a floppy drive and, of course, a floppy disk. Once the drivers are loaded, you should be able to see all the partitions on your array.