ACHI Problem XP

I am using (2) WD blk 750's, 970A-UD3.Hard Drives connected to SATA 0 & 1.Newer board.Came with f4 bios.

My objective:

I run 2 versions of Windows- XP Pro 32 bit,and Windows 7 Pro 64 bit.I want to run in ACHI mode in xp.I wanted to have achi drivers for xp before I installed 7.

I have (1)750 gig hard drive set up for a dual boot between xp & 7.I slip-streamed the achi/raid drivers to a custom disk.Rebooted pc,and went into bios and set achi mode,saved and re- booted,installed xp,added all my drivers,reboot and all is good.

Here's the problem.I added another 750g drive into the mix,after everything was running smooth..I am able to see the drive in windows and write to the drive,but it bios it does not show up.My main drive,according to bios info, indicates one drive,not 2.Hirens boot gives me the same bad news.In the device manager,in XP the achi/raid drivers are listed as my current drivers,so its running in achi mode.

I switched back to native ide mode and all works good like before,but this time my bios indicates 2 drives.I am adding a ssd drive as a main boot,so I can run windows xp,7,and games on the ssd,but my additional drive is not recognized in achi mode.

I'm at a loss here.....