Paper material sphere bending simulation

Hi,

I'm now doing simulation of bending sphere made by paper material.

It's actually quite good working but I would like to bend inside of sphere.

Dose anyone know how to bend, actually forcing bending, inside of sphere ?

Here, there are original file and screenshot showing how it works. I will add description more in next.

I tried "CollideSurf" component but it is too much forcing so that I could not bend sphere.

Regards,

Maru