Physical properties of Surface parts in Inventor

[desaia]

Hello,

I have a curved plate modeled Autocad using 3D faces.
I want the surface area of that part.
I have no idea, if Autocad can show surface area of that part
So I imported that in Inventor 2008 as a surface part.
I tried going to iproperties for a part, selected a material "mild steel" but i get 0 value for
area, volume and mass.
I understand it has got not thickness, but i would still like to have a surface area shown.

I would really appreiciate if somebody can help me find the way to calc. (figure out) surface area of this part using Inventor / AutoCad


Thanks,

Avani