Hi Shawn,
Yes , if it's only the 200mb system partition - you're right , it's best to include it.
This is for if your Vista partition is the System partition - and you don't want to include all that in the same image as 7. You might not have space, or you might prefer separate backup images.
In fact, I have just changed my System partition from the First (Vista ) partition , to the second (7) partition.
I have the relevant boot files on both, so if I want to change back, I only need to swap the active flag back to the first partition.