HDD SAS in HP Z840

Hi,

I just bough a new HP Z840 with 6HDD SASx600Gb. I trying to install Windows 10 64bit but system just recognize only one HDD in SATA slot + DVD driverif I put the option AHCI in BIOS. If I put in RAID mode, no HDD be see by WIndows setup even I have the LSI SAS2 2308 Mustang install showing.

Any advise ?

Thanks

Long