External Memory BF706

Hi, 

I am working with an example code "BF707_SPI_Flash_access_codes". From its system.svc -> Startup/LDF, there is a option which the external memory can be set 

But in my case, I am using BF706, and from system.svc -> startup, there is no option for setting external memory. 

Anyone can explain to me, what I have to do instead for?