Windows 7 built-in speech recognition

Dear members,

I just installed Windows 7 on my machine and found they have quite nice speech recognition system with OS.
I have installed Speech SDK 5.1 to another machine on XP before, wonder Windows 7 has such SDK for us to customise the functions or usages.
What I want to achieve is to limit the recognition only to a certain application (i.e. my app).

Appreciate your help.

Regards,
chris