I've considered using a script I have - using iwextattr - to extract, manipulate and reapply - but didn't want to miss a more efficient solution.
You're right in assuming that the EA is the only place where this is stored, so what you're asking for is a way to programatically update this ea (G11N/Localizable) on a large file set. PERL script is quick to write, but slow to run. Java will be orders of magnitude faster, but there's lots of hoops for a throwaway script. The decision maker is whether you're going to reuse this thing on a regular basis (e.g. we customized our file import screen to use a custom servlet as its done_page, so that we can update this EA as soon as a static asset is imported into TS).
