Hello all,
In my APEX 5 app, I am trying to get a translated messaged to show up in an apex.confirm call on button click. I'm attempting this using the apex.lang.getMessage API, but it does not seem to be working for me. So, to start out, I created a custom message on the Globalization > Text Messages screen like so:

The button on my page is defined with a link behavior like this:

javascript:apex.confirm(apex.lang.getMessage('SFI_RELEASE_PICK_WARNING'),'P16_UNBOOK');
As far as I've been able to find, this seems like it should be all I have to do. However, when I click on the button in the app, All I'm getting is that message code back:

I also tried using the standard APEXIR_ACTIONS message (and a couple others), but got the same behavior: displaying the code and not the actual string.
Any help you can provide would be greatly appreciated. If there are any other ways of accomplishing a confirmation dialog like this before submitting a button action, I'd be open to hearing them.