Creating json target file with utf8 and bom

In a Passolo 2018 project we have some new json files, encoded in utf8 with bom (byte order mark). We are looking for a setting to get this encoding in the translated target files. They currently appear as json in utf8 without a bom. 

It must be possible, because we have a different json file (in the project for a few years) for which the target is written as json utf8 with bom. Perhaps there is a way to copy these settings? Have checked the help for project settings, target rules, configuring JSON add-in...

Thankful for any tips.

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