How to implement xcodeConfigFile desired capability in Maven project?

There is a known signing issue with XCUITest (see Issue Here and the proposed solution is to add an xcconfig file to the project which includes values for:

DEVELOPMENT_TEAM = <Team ID>
CODE_SIGN_IDENTITY = iPhone Developer

Then, the full path to that file can be passes as a value to the desired capability named xcodeConfigFile.

I am new to using Maven. When I add xcodeConfigFile to my properties file in IntelliJ, it is greyed out, meaning it is not being displayed as an acceptable capability. I am not sure what I’m doing wrong. My properties file is as follows:

platformName=iOS
platformVersion=9.3.2
udid=<UDID>
deviceName=ipod
noReset=false
app=<app>.ipa
xcodeConfigFile=~/path/to/config/myconfig.xcconfig
automationName=XCUITest
hubURL=http://0.0.0.0:4723/wd/hub
appiumServer=true

I am on Appium version 1.6.3

I am not sure if this ties into the issue at all, but I am also not sure which file type to use for the .xcconfig file in IntelliJ. I have tried both a text and properties file.

Any help would be greatly appreciated.