i think you are going to have to learn some c# as this is what the scripts for missions are written in.
As i understand it (huge caveat here
) the only way to access the .dll is this way. In theory you should be able to use only a little scripting here to actually access the data and point it to an 'add in ' dll ?(which could be done in c++?) to do the grunt work of ordering the data into a format to output it to the G seat (making huge assumptions above my pay grade here)
Again in theory c# shouldn't be too much of a jump for you- java/c# both being object oriented languages- just the syntax being different (infact the little i know i actually used a java book to explain some of the concepts used in c#)
You really ought to make a topic in mission builder forum
http://forum.1cpublishing.eu/forumdisplay.php?f=203
where the experts (FG28_Kodiak in particular) are more likely to see it and point out correct/better ways of doing this stuff- i really get lost past VERY basic stuff.