3rd Generation Under-floor storage compartment

I have a Prius One so it doesn't come with an open flat under-floor storage compartment, instead it comes with a styrofoam divided compartment area instead. Does anyone out there have a standard under-floor storage compartment available? I am not sure if the after-market compartment divider sold as an accessory fits inside the standard lining or replaces it, but if it replaces it, then maybe someone has no need for the standard lining?

 

Thanks for the information! I was hoping it was a complete replacement like my poor man's version seems to be.