Rob1n, have you thought about posting a licensing request on bugs.maemo.org asking them to open-source whatever component it is that handles the autocomplete dictionaries? I don't know how likely they will do that, but it's gotta be better than trying to reverse engineer things.

If they won't open-source the code, maybe they could at least document the file format. Or maybe there's an undocumented API for manipulating it that they could tell you about.