.Net version in Server Code?

From the install of version 9, I would have expected .Net 3.5, but it appears that the C# code that is used in the server scripts are compiling to .Net 2.0.  I tried to use a lambda operator to define an action to pass to a class, and it fails.  This is pretty limiting if there is no way to program higher than .Net 2.0....

I mean really guys - we are on 4.0 now with newer stuff on the way soon....

Does anyone have any tips on this?  Any way to get at least up to .Net 3.5?  This would open up a few more things...  And 3.5 is just a version 2.0 with all the newer features anyway.