ELRS with Orange Cube+

Hi friends!
I have stacked in problem - I don’t understand how to connect a ELRS receiver to the orange cube+. I read a documentation where found out that I can connect my receiver to RCIN or SBUSo. For SBUSo I tried to work with UART5, for example, but didn’t have success. But I wasted several day but can’t understand how to do it. In both cases, I don’t see signals from my receiver (page “Radio Calibration” in MP). Please, help to solve this problem!!!

I tried to connect my receiver to UART 4 and it works fine, but I need this UART4 for another task. Are there any decisions on how to connect ELRS to RCIN or SBUSo? Help, please