View capacity of DFS volume

Hi,

My question is about DFS on Windows 2003 R2 SP2.

I've a files server with :
- C: (System) -> 20Go
- D: (users data) -> 1To
- E: (VSS) -> 100Go
- F: (DFS) -> 20Go

DFS have been create on F: and point to D:. It was a domain DFS.

When i've mapped on my client the DFS to \\NOM_DE_DOMAINE\NOM_DE_VOLUME_DFS
I've a capacity of my F: drive and not the D: drive.

I've a 20Go drive and not a 1To drive.

I don't know if it's good and if i've a possibility to see a good capacity?

Thank's.