So far, when working on WordPress projects, I always hit a point in time, where it was necessary to create or alter .po files for themes or plugins, to be able to use them with a German website.
Especially when working with more than one translator (possibly not even having the necessary software) or having to support multiple languages, it becomes very complex and time-consuming. A few weeks ago, I coincidentally came across a plugin, which I have since installed on all(!) my WordPress installations: Codestyling Localization by Heiko Rabe.