S800 I/O used with Safeguard415

We have a customer with an Advant Master system with 800xA HMI.

They have SG415 (redundant) installed with some I/O that has been proposed upgraded to S800 I/O with AF100 bus (proposed by ABB)

Do you have any documentation on this solution? Can you use one port from the CI522 module in each of the SG controllers and then use two CI820 to get a redundant solution? Will this work?