Is there any way to load .net 4.0 runtime with Vegas 9.0?

Recently, I've tried to write down extension dll with Vegas 9.0, and found that Vegas scripting is hosting .net 2.0 runtime.
With some of reasons, I want to use .net 4.0 framework with my extension.
(linq, async task, etc...)
I've tried with Application configruation file (.config) with lots of exe, dll in Vegas folder but failed.

Thanks in advance.