what kind of naming convention do you mean?The tool from the menu Tool | Naming Convention is not designated for this purpose. The naming conventions can be used to define rules for customs names of objects, not for the default names. For this purpose is better to specify default name of the relationship on the from Default values (menu Settings | Default values).
You can also change the name of FK index on the same place as the name of the foreign key (I.e. it the Option | Physical model | General | Index to Foreign key name.