I'm confused. This is how I've done what I think you are asking for.
In the Show box, click on "Life Dates". Now each box should show a name at the top (might span two lines), then "Born xx mmm yyyy" and "Died xx mmm yyyy" in two rows under the name.
Next, again click the Show box and this time click on "Surname at birth", which is the last item in the popup list.
At this point, each person (probably primarily females) in your tree should show their maiden name.
If not, select one of the people and look at the "Personal" tab in the sidebar on the left and then click the "Edit my details" button under the dates. Confirm that you have different names for "Surname now" and "Surname at birth".
As I said, this is how I have mine setup, and every one of the people for whom I've specified different surnames show the "at birth" one in my tree.