iOS Tester Only Features

I am trying to point my app at the production server for final and beta (TestFlight) testers but for alpha testers I want them to to get an extra little button.

My target is set up to have Build and Release variables and those are working fine:

//:configuration = Debug
BASE_URL = http://ift.tt/2lhOzDK

//:configuration = Release
BASE_URL = http://ift.tt/2lcHxTM

And then I can just enable disable the button (Swift 3) :

#if DEBUG
    // We can leave the button
    ChangeServerButton.isEnabled = true
#else
    ....etc

So far though, the only time I see my button is when I use XCode (8.1) to run directly on my phone. The process of "Archiving" seems to only create release software.

Surely I am just missing something obvious here. Would anyone care to jump in?