Start AP with hidden IP

If you are running Espruino on an ESP8266 the code is part of the binary flashed to the device and will require one of the ESP8266 GURUs to make the changes and recompile the code.

If you are using the ESP8266 from another Espruino device through a serial port the code is in the module on the website.
To make the changes copy the module from the website and paste it into a file to edit.
On WebIDE options page create a project directory (if you haven't already). Put your edited module in the project.modules directory. Suggest that you rename the module and change the name in your test code. When modules load WebIDE looks in several locations for the file, one being the project modules directory.
As a first edit insert a console.log("It's me"); into the function you are going to change and see if you are on the right track by running your test code.

For ESP8266+Espruino, the ESP8266WiFi_0v25 module provides a function called createAP