IIRC the G5 models were introduced in 2006 or 2007, and either had an E200 or P400 SmartArray controller. Anyway, pressing F8 when the RAID controller shows up while booting the server should bring you to the ORCA (Option ROM Configuration for Arrays) where you can setup the RAID configuration. You actually only need SmartStart CD if you want to e.g. configure multiple logical volumes on the RAID sets, as ORCA will just create a single logical volume once you setup a RAID set.
André