R9 mini and X8R for redundancy

[pcwizzul]

I managed to connect with success a R9 mini to an RX8R to use the redundancy option and it seems to work great.
I followed this tutorial and connected the SBUS out of the R9mini to "RX IN" in the RX8R and eveything works amazing.
I had a friend of mine turn off the integrated module of my Horus and trasmission switched to 900mhz without the smallest glitch (amazing btw!)
But we were wondering if we could connect the R)mini to a normal X8R, maybe through the smartport.
I'm afraid not, but I wanted to ask, maybe there's a way to do it.
We are on Opentx 2.2.3 and R9 with latest firmware (not FLEX).

[Kilrah]

No. That possibility is a new feature of the "RX" receivers.

[pcwizzul]

Thanks Kilrah for your precious help.
In the meantime I bought another rx8r and another r9mm but I can't find a way to bind the new r9mm. I tried changing firmware on both the receiver and the module, tried even the flex firmware but to no avail.
Green and red leds remain solid, on the other r9mm receiver eveyrhing works flawlessly. Any hint?
Thanks again