Please provide more details.
Which Designer version are you using?
What steps did you take exactly?
I believe you have set the "Foreign Key Field Pattern" in the project settings, correct?
What's the value did you set it to?
Did you test the results with newly mapped entities (first time reverse engineered), or on existing entities?
i.e. Did you set the project setting, then mapped an entity and generated the code?
Or did you set the project setting, then regenerated the code and checked the FK name on an existing entity?
Thanks,