I'm going to show you how to save that edited Shape.  First make sure to Select None.  You have added that to your toolbar, right?

Give your Shape a name.  Ok, it's there now, but it could get confusing because it has the same name in the Shapes Library even though you named it Sphere Purple.

Here's what you have to do before you Export it.  In the Layer Palette, click on the current Shape name, Sphere2, so that it is highlighted.  Now right click and choose Rename.

So as to keep things straight, I choose a new name, Sphere Lavendar.  Then I Export it to Shapes again and name it Sphere Lavendar.  Now I have a new Sphere that won't be confused with the original one.  Opps!  I actually have two new Spheres now.

Here's how you fix that, and you need to learn this for other changes you might make in Brushes, Frames, Gradients, Patterns, Shapes, Styled Lines, Textures and Tubes.

The information for them is stored in the Cache folder in PSP7.  First go into the Shapes folder and delete that first Export, Sphere Purple.  Now go into the Cache folder and delete the Shapes.jpc file.