Hi Ron,
First thing I would like to do is put your mind at rest about the drives not displaying in the BIOS. I can't explain the actual details of why it works this way but it is to do with the way Gigabyte codes it's BIOS and it confuses many people.
As long as you have set the controller mode to AHCI in the BIOS and everything is working alright then dont worry, everything is normal.