I'm not familiar with the E400 command line, nor the required commands to create a User-Define Override on one of my E400 AP's. I have an SSID setup as WLAN 4 and I need to disable that WLAN/SSID on just one of my AP's. I am using a cnMaestro AP Group to push out the settings.
The end goal is to be able to continue making edits and updates to my network in cnMaestro without having to manually disabled WLAN4 on this one AP.
It is possible to disable a WLAN on a single AP using User-defined Overrides. In your AP Group add the following text to the User-defined Overrides section. Change the WLAN number to whatever is appropriate for your specific AP group based on the WLAN ordering you specified.
wireless wlan 4
Applying this as-is on devices will cause no change.
Edit the User-Defined Override of the device for which you would like to disable the WLAN (Configuration -> Configure Devices, click the Gear icon on the far right of the table for that device's row). Scroll to the bottom and enter "shutdown" in the text box next to SHUTDOWN. Click save and push the configuration. That device will then have WLAN 4 disabled.
I tested this locally in my lab and was able to successfully shutdown a single WLAN this way. Devices that did not have their User-Defined Override value set did not have their WLAN disabled.
Nowadays you have a GUI option for this on cnMaestro. Go to the AP where you don't want to see the second SSID. Click on the "Configuration" tab. At the bottom you will "Device Overrides (Advanced)" option. Within it you will "WLANs" tab which you can make use for this.