I've just uploaded a new version of the FSAverage atlas, which includes the Brainetomme atlas:
https://github.com/brainstorm-tools/brainstorm3/commit/ffbdb4dd8ef6207aa58d425929f047ede96d90e9
To get it: update Brainstorm again, then right-click on an subject folder in the anatomy view > Use template > Download: FSAverage_2020.
If you have the MRI of your subjects, you should rather run FreeSurfer and project the Braintomme atlas on their own cortical surfaces.