You can add Dutch as a language to your project. Move all the US captions to the Dutch captions by using the language operations functionality in the Modeler. Delete the US language and set Dutch as the default language. Result: Ducth date format, US English captions and texts.

Why are you doing this in the first place? Localization is invented to apply to the conventions, and now you explicitly go stray from them. Any native English reader will severely be confused with a date such as 02-04-2002 and currencies will look funny.

Half of the dutch people on the other will be confused as well, since they might expect English dates in English text, but they can't be sure anymore...

The solutions is not to do this kind of strange things, but to use a date formatting which is clear to any reader, such as '2 April 2002' or 'Apr 2, 2002'.

Or just support both languages in your application :)

No, this isn't possible. The locale is always based on the language you choose.

Can't you use the 'Localize: No' option in the domain model?