Updating a cpatured program - loading master machine to just before final snapshot

Hi, I was wondering if there is a way to load your 'clean machine' back to the point of a capture just before you end the capture and built your thin app. This would save me a lot of time on updating one of my packages that has lots of parameters that need changing. i.e. I would like to:-

1. start initial capture on vanilla machine image
2. Install original software and make all changes
3. end capture and build app.exe

Then 6 months later when an update to the app comes along,

1. Power on Vanilla Image PC
2. start capture process
3. somehow load machine to same position as it was just before step 3 above by using previous captured data and without re-installing the software again
4. install updates and make any new changes
5. end capture and build a new updated app.exe

I have seen how to do side by side updates and sbmerge etc, but they seem to imply you have to start the image capture from scratch and not start building the image from where you left off on the original build.

Thanks in advance.
Kevin