The SR2612UR uses a SAS expander, which requires a SAS controller. It doesn't work with the onboard SATA connectors.
I purchased with the Intel® Integrated RAID Controller SROMBSASMR2 (AXXROMBSASMR) and it just works fine after I configured all the six disk in a DG with RAID 5.
Thanks for the update. Glad to be able to help
Why this is not in the server configuration tool ?
I have lost time and money with this issue