Enable guest SSID via script

[asus09080980]

I am trying to make a script that will automatically set up a guest network. I can apply settings like the SSID and password if the interface is already up, but I cannot get the network working without turning it on in the Web interface.

So for instance, I want to run these commands:

wl -a wl0.3 ssid "Guest3"
ifconfig wl0.3 192.168.4.1

But end up with these errors:

wl: wl driver adapter not found
SIOCGIFFLAGS: No such device