I have a similar device I use on my A4000T IDE header. They are not hot swap though. It treats it like a hard disk is all. You will need to still reboot to have a new card show up.
But the question was about the SCSI bus, not IDE. You can get such devices to be shown if you rescan the SCSI bus for example with the UnitControl program (I don't know if this or other devices are designed to be used like that, but IIRC I've done that with removable SCSI harddrives years ago).
