Are you configuring SATA RAID as Matrix Storage or Intel ESRT2?
Either way you don't need to mark a drive bootable. Actually you only mark a Volume (or VD) bootable, not a physical hard drive.
If you're using a hot swap backplane you can hot swap the failed HDD and start the rebuild from the GUI. You can also connect the new drive while the system is off, and rebuild should start upon boot. No you don't need to do anything to prepare the new drive. Just make sure it's blank and doesn't contain any previous RAID configuration (e.g. you haven't created a RAID volume using that disk on another machine).