Our house has interior walls studded with steel studs. The house was built 20 yrs ago and just now installing baseboard. No backing is between studs to catch the nails or screws between studs. Baseboard is natural pine. I'm thinking I may have to use screws into the studs then plug the holes with a wooden plug. Any other suggestions? Outside walls are ok as they have wooden studs. We do not plan to paint the trim.