What you show is NOT HTML formatting.
Sure that you shouldn't be specifying Plain Text instead of HTML? Some Email clients do not correctly handle returns if they are set up to send HTML encoded mail from FileMaker and need to have plain text specified instead.
I apologize for my mis-labeling. What I mean to say is that the operators do not carry over.
The Entourage client has always been set to send plain text only - the only thing that changed was the Filemaker Version.
Please note that I'm guessing here as I don't use this email client nor this OS....
If the only thing that has changed is the FileMaker version, have you checked to see if there is an update available for Entourage. You never know, you might get lucky.
And I'd double check the settings on entourage just to be sure. I can find a note in the Known Bugs LIst that MS Outlook has this exact issue unless plain text is specified in Outlook....