Mr, Vance, thank you for you help and attention!
I took all the precautions and solutions you gave me. I also ran ADU and attached report above.
Neveretheless, the problem has gone away after server reboot. During post the bay 1 green led lit and finally rebuild process was started with the new disk installed. The one thing I still don't understand is why the reboot was nessesary, why the hot replacement with the clear disk wasn't enough.