OK so i took a dive into the Java classes last night and i think i understand what needs be done to add new radio-stations. There are still some things that are a bit confusing (this is my first attempt at modding Java in Il-2) but all in all it doesn't look too complicated to clone the existing radio-station objects and modify them into new ones. Stay tuned for further updates!
On the other hand, replacing / updating / extending selections of the music files in existing radio-stations is very straightforward. It's more of a matter of making a decision what to do with the already existing stuff (i don't want to crap onto anybody else's work) - so if anybody has an idea how to handle this, i'm listening.
(mainly what i'm concerned about here is to have all radio-stations "speaking" correct languages - right now Hungarians "speak" German - and give them music with more national flavor rather than generic 1940's American jazz and swing; not that there's anything wrong with Glenn Miller
)