actually working on this right now for the storm. Here's what I 've found so far. Greek itself is part of a language package. What you need is the last known os with your multi language support. copy/paste ALL language related .cod files. It's quite a large file but you dont need to run all languages on your device.
As of right now I was able to get greek, italian, portuguese, dutch and a host of others working on the latest release from VZW which doesn't support these languages. The key is to find the one that supports text input and understanding the language will save you alot of headaches.
It's a trial and error thing though lol If you attempt it make sure you know how to recover a bricked device...
Bellshare - Premium Blackberry Apps