MCU SPI in Master mode with Software slave management enabled, Slave is a third party zigbee device which expects its nSSL to be driven externally

Question

I am using my MCU (STM32L486) as the master (SPI) and a zigbee peripheral is the slave device. Currently the master is configured (SSM = 1, SSI = 1) with Software Slave management.
As the slave device expects its ChipSelect to be driven low and high respectively. I understand there will be a need for a GPIO to be used for this purpose.
The pin pack for SPI operation used is (SCK(PA5),MOSI(PA7), MISO(PA6) and NSS(PA4)).
I am confused on the usage of NSS pin.
Since the Master SPI is configured as Software Slave managed, Can i use this (PA4)pin to drive the Slave SSL signal or i cannot use this pin at all. As the reference manual suggests but the notes in the below section (highlighted yellow) suggests that both the master and slave has to be handled internally.

Does it mean i cant have the above configuration?, where
1. Master SSL is Software managed.
2. Slave expects its SSL line to be asserted/deasserted externally.

Please provide your insight. I am working on an already written code. There are some issues in the product and i am trying to debug it.

Answer 1

I have posted the same question in st community forum. Response From ST community They have replied back by saying as long as i dont configure the SSL(PA4) as an alternate function pin, i can use it to drive the slave.