I'm playing .11.0d but my save maybe 11.0c at some point can't be sure too many updates recently.
I have made her a servant with a scroll.
The servants seem to keep also their trained slave bonuses which is cool.
Sadly, they don't have any training as a Servant. Even a combat slave isn't trained for combat as a servant. Apparently it's the same for a date skill even if the former slave was trained for it.