No AHCI With XP

My new system has and Asus P5Q turbo MB, one or two SATA hard disks (SATA1 and SATA2 connectors) and one or two IDE DVD writers.The exact number of drives doesn't matter.If I set the IDE & SATA controllers as AHCI in the BIOS I have no problem installing linux.With windows XP (SP3) I get "no hard disks in system".Switching the controllers to IDE in the BIOS I'm able to install XP but, of course, the drives are not used via AHCI and linux has some problems.I found no way to make XP use AHCI once installed: if I change the BIOS switch then XP doesn't boot; if I keep the BIOS as IDE the Intel installer says "prerequisite not fulfilled" or something like that.I tried making the floppy with the Intel AHCI drivers (either the ones in the MB CD, the one from Asus web site and the newest from Intel), pressing F6 during XP installation and selecting "Intel(R) ICH10R SATA AHCI Controller".

By the way, during this process XP says: "windows already has these drivers but the one you selected are newer".All is fine, XP can see the HD(s) and the partitions and can format the partition, until XP reboots. At this point I get "can not find IaStor.sys" and the HD can't be seen anymore. No way to continue.As suggested in the motehrboard user manual, I tried adding to TXTSETUP.OEM:I'm positive about the vendor ID and product ID of the floppy driver.I also tried putting the floppy data in [HardwareIds.scsi.iaAHCI_ICH10R]