Trunk panel

On the 69 barracuda i,m doing for my wife the panel between the fenders at the bottom of the window is rusted thru. The car is a notchback. Does anyone know of an after market panel for this or do I have to find a donor car for this panel. What is the proper term for this panel ,is it called the sail panel? Anyone with this part available or knows where to find oneI would certainly like to hear from .Thanks