You'd think that would be an option, but I've never added support for it.
Rotation periods are extracted from the Data files and I added a special action called rotationperiod...
<Action>rotationperiod=faceparent</Action>
...but faceparent is the only parameter it currently accepts.
Sorry about that... I've added it to the list of features to add to the upcoming version.
If you use the <Object> property and then override all the other attributes it will have the rotation period of the body specifed in <Object> (assuming this object has a rotation value in LocalObjects.xml or Stars.xml).