Hi coop, welcome to NST.
If you use the search button at the top of the page and look for "winpe" threads, you'll find a couple from July which might be what you're looking for.
Actually I found some threads, but none of them explained what I would like to do. I'd like to start the software from a winpe booted on an external device. And use the software to fix the Windows Vista bcdstore. I don't even know if that's possible actually. Can you point me to those threads?