cc6 wifi AP config

If I bring up the wlan1 interface on a CC6 the device serves up a WiFI access point configured by file /etc/hostapd_wlan1.conf. Is this file specified in a driver somewhere or is a pointer to a file built somewhere else?

How do I override or change that file as it resides in a write only partition?

I want to substitute my own conf file in order to bring the AP up with my own ssid and password. ( this is changed on the fly every time I bring up the interface )

Alternatively is there a way to change the ssid and password from the command line and / or from a piece of code?