AutoCAD Civil 3D

[#1]

I have a question about C3D and the pipes properties. When I edit the pipe
structure for a network within my drawing, I have the option of different
materials. PVC, Corrugated Steel, Ductile Iron and Reinforced Concrete.
Now in the pipes catalog, each of those associated types have different
inside diameter value sets associated with them.

However, if I switch from say concrete pipe, to pvc, the associated values
in the structure editor don't change. With PVC pipe I should be able to go
as small as 75mm pipe, but the smallest inside diameter in the structure
editor remains at 250mm (the smallest for concrete pipe).

I guess my question is, am I stuck with the diameters for whatever pipe
material is chosen when I first create the network?

It would seem to me that when editing a pipe structure, if you change the
material, your associated diameters should change as well.