DEVIATION RX-703 from a Walkera 350 Pro

Someone try to get the RSSI signal from this transmitter, ? for this TX does not exist a diagram or any other info , so i would like to get the RSSI to my FPV monitor using EZOSD.

Is not a problem to soldering but i don't know where is the PIN:)
if someone has any idea , it will be nice , or another way to get RSSI on FPV using RX703 and DEVO-M

I don't want to change RX just because of this reason,

thanks ,