Why "cfgadm" does not show "med-changer" device of SAS attached tape-library?

Trying to set up a tape library **NEOs StorageLoader** LTO7 and also old **PowerVault 124T** I am facing following problem and cannot find any helpful answer. Using either **Openindiana 151a8**, **Openindiana Hipster 2017.4** or current **SmartOS** none of them creates device for tape-changer LUN1 (to be used by **mtx**). Only tape-drive device (LUN0) is shown: user@server1:~# cfgadm -al Ap_Id Type Receptacle Occupant Condition ... c3::rmt/1 tape connected configured unknown ... Which maps to /dev/rmt/1 and is perfectly usable by **mt** tool. I have read a lot about using **devfsadm -C -v** and booting with reconfigure option but nothing solved situation. How to get **/dev/scsi/changer/...** for **mtx** ? BTW: Tape library is attached to LSI 9207-4i4e HBA controller and OS driver for this is **mpt_sas**, which seems to see LUN1 according to LSIUtil and boot screen output. /var/adm/messages does not show any useful info execpt a warning, that multipathing will be disabled due to invalid WWN of tape-changer.