I have a lot of double sided projects I created before v9 that I have left as is. It seems harder to convert an old project then it is to just start over (at least for me).
Here's what I did to create a bowl.
Set the project size to 10"x10"x1" (sorry all imperial
I start with the bottom, why? because it just makes more since to me.....
In the Modeling tab I added a Zero Plan
I added a 90° dome and sized it.
I set the component to Add and height to 1"
I then created a Vector Boundary around the dome.
I then clicked on the dome and copied it to the front side.
On the front side I resized the component down by 90%
I created a Vector Boundary
Change the component to Subtract
On the Toolpath tab click on Material Setup
Set the Thickness to 1.001" (Model Position doesn't like a model thickness the same as the material thickness)
Created the toolpaths as usual using the Vector Boundary on the back side to cutout bowl.
Hope this helps....