Selenium IDE pull Parameters/Variables from config file running through Selenium-side-runner

I would like to be able to pull my authentication parameters from a config file.

My .side.yml file currently contains:

capabilities:
    user: "admin"
    pass: "only_4Admin"
    browserName: "chrome"
baseUrl: "http://QA_Testing/Login"

It reads the file okay as I'm able to change the browser from here.

In Selenium IDE I call them using ${user} and ${pass}:

type | id=Username | ${user}
type | id=Password | ${pass}

The test types 'undefined' in the username and password fields.

The cmd I use to run my test is:

selenium-side-runner C:/Temp/IDE/project.side --config C:/Temp/IDE/.side.yml

and also tried:

selenium-side-runner --params "user='admin' pass='only_4Admin'" C:/Temp/IDE/project.side

Neither work.

Any help would be great :)