Great little program.
There is a problem with USR not showing the “Config Disk SCSI Disk Device” (aka SteelVine disk) that represents the SiI 4726 processor in the five-drive AMS Venus T5 eSATA enclosure, which prevents the enclosure from being stopped gracefully.
The program Hotswap! does correctly display the config disk plus the five hard drives of the enclosure, and I'm currently using it to stop the enclosure.
I already bought USR (fantastic value for the unlimited license -- thank you), so hopefully this issue can be addressed in the future and I can rely on this program alone.