I already answered this on my Post, but here it is again:
Okay, so I managed to get what I wanted with a widget. It's only until Mendix fixes the issue.
Its very short, and doesn't use a lot of code and has the advantage of switching language at runtime on demand
Here's a Youtube™ video if you want to see it in action.
Tested with Mendix 6.9.1: Github
You could take a look at this AppStore module and see how it works. It's 6.1 compatible.
Unfortunately the module does not work in 6.8 and 6.8.1. We have also tested the module in 6.7.1, but here the language did not change dynamically as well. Any other possible solutions?