What, cant set a raid setup with mobo...

i have a asus m5a99x evo and a ssd and two hdds i want to set in raid 1.

to do so i must enable each sataIII port to be "RAID" but also need it to be AHCI for my ssd. the mobo only allows either raid or ahci. the mobo groups sata ports 1-4 together and 5-6 together. cant assign one particular port to a certain standard. if i assign 1-4 to be achi, 5-6 go with it and visa versa. the only time when 5-6 can be different is if its selected as IDE, then 1-4 can be either RAID or AHCI. isnt this a bit useless?

any ideas?