hey, johan -
i think you can simply add the file to the completed jar. then you load the file from the har. i had to
do it with my tesseract library years ago. it definitely worked. erel provded an interesting routine (attached).
see if it makes sense to you.
tesseract's english data file is called eng.traineddata. i simply dragged it into the jar. somebody asked about a problem similar to yours way back sometime.
look
here i think that's where it comes from...