When faced with the possibility of having to establish a legal system for Bretonia, in order to allow for criminal and civil proceedings to occour, it was deemed too time consuming for the Admiralty to deal with.
We have zero desire to mediate a dispute in this fashion, the none of us have the time to do so. This meant, upon agreement, that Summary Justice will be the only in game method of justice in Bretonia. (This is not done to stifle RP, but to avoid undue and unneeded paperwork.)
Since you are attempting to try a BAF officer, in a civil court situation. As Dab has stated, the Admiralty has the right to shut it down.
Do you know that there is a real life law preventing anyone from suing military forces in a time of war?
Well consider this law in effect for Bretonia. It will be entered into the Bretonian legal codex as soon as possible, to prevent this from being an issue in the future.