BuddyPress.org

@xevo

If the dutch language pack comes with both po’s and mo’s, then you can rescan the buddypress directory with poedit, update the database from the source, and then proceed with your changes.

If not, then you’re sort-of out of luck I think. I haven’t found a tool to merge an existing mo into a new po, so it would be a manual process of copy and pasting each preexisting translation.