component out of a scetch
 

Hello,
The picture underneath shows 2 circles. The outer circle was used for Außenhaut/Ausformung (I dont know the english word) and the other I wanted to use to specify a component region. Though, how do I do that?
I havent really figured it out...The way I did it here is I used surface through scetch (Oberflächen durch Skizzen). But this gives me an entire new body (Schalenkörper) additionally to Volumenkörper (volumebody?) which is not correct or?
What I also noticed is that even though I specify the new "surface through scetch" as a new component, when selecting it in fluent it chooses the entire region of the bigger circle!?
So how can I properly define a component region within an already given surface bordered by the outer circle?

http://imageshack.com/a/img908/6110/vMF86a.png