Dutch translations for formExtension validation messages

These are just translations for the validation messages.
I still need to figure out how to inject translations into the notify templates, now there's stuff like 'The following fields have validation errors:' hardcoded there.
Yet, these templates are set in a config() block of the aa.formExtensions, so I don't have access to the other translations there yet. So, merely adding them to the formExtension validation messages isn't a solution.
Need to figure out what a nice approach is, any suggestions are welcome ;)