In AWS API Gateway - how do i set stage variables for the test-invoke-stage?

When I invoke my API from the AWS Console, I notice that the stage name is "test-invoke-stage".

I set up some stage variables to have my mapping send to my lambda function but those values are coming in blank. When I try to set up the test-invoke-stage so that i can set the variables for that tester, it says I can't name a stage name with the - in it .

So how do i use the test invoker and pass in stage variables?

What is stage variable in AWS API gateway?

There's a new feature on Amazon API Gateway called stage variables. Stage variables act like environment variables and can be used to change the behavior of your API Gateway methods for each deployment stage; for example, making it possible to reach a different back end depending on which stage the API is running on.

At this time 12/2015 - its not available - the question was answered in a webinar with Amazon. They said it is a feature on their roadmap. When i see it, I'll update this question/answer.

Update - its now available to add in values for stageVariables when you do the testing in the web console. (2016-01-14)