Indeed, the function in_data_fieldtrip.m does not read any event from the FieldTrip structure:
https://github.com/brainstorm-tools/brainstorm3/blob/master/toolbox/io/in_data_fieldtrip.m
It is probably easy to add a few lines to this function to read the events you are interested in.
Can you please share an example file?
- upload the FieldTrip .mat file somewhere
- post the download link here
- describe precisely what structure of the file you would like to read, and how you would like this information to be available in Brainstorm