Thanks for the clarification.
Could you send a few sample messages to firstname.lastname@example.org, please? It would be helpful if you include both the saved message (FML file) and the original GroupWise message (as an attachment) for comparison.
In addition, please send your Formativ configuration. You can obtain the configuration by selecting Help | About Formativ… from the GroupWise main menu. When the About Formativ dialog appears, go to the Configuration tab and click the button Copy to clipboard. Then paste the text into your reply email (or save it to a plain-text file and include it as an attachment).