[CentOS] Order of sata/sas raid cards

Hi.

I bought a new Adaptec 6405 card including new (much larger) SAS drives (arrays).

I need to copy content of the current SATA (old adaptec 2405) drives to the new SAS drives.

When I put the new controller into the machine, the card is seen and I can see that the kernel loads the new drives and the old drives. The problem is that the new drives are loaded as SDA and SDB, which then stops the kernel loading, becasue it cannot find root and get kernel panic.

Is there a way to tell the kernel in which order to load the drives and assign the drive order in a way that the new drives are assigned SDC and SDD and the old drives get SDA and SDB?

thanks Jobst