I realized that, when I posted my original request for a schematic, I'd said I'd post my solution in a separate message.
I was able to adapt the SCSI backplane in my SR2300 case to accept SATA drives. It involves hardware modification, and no, it doesn't somehow convert the SCSI bus to use SATA drives. It will serve my purpose; however, I'd love to try a neater version 2 with unnecessary components removed. I'd still need the schematic for the backplane to prevent my removal of parts necessary for the floppy-CD/DVD-rom drive and front panel parts to still function.
I hope this information will help someone else keep their older hardware alive a bit longer.