I have posted a detailed tutorial on my blog,
Stamp and cut with a Silhouette « Clever Someday
but here are the general steps:
-Cut a plastic template to facilitate drawing registration marks in the proper location around the stamped image. This is a one time process and the plastic template can be used with that stamp and the corresponding SS file indefinitely.
-Tape the template in place around the image and use a pen to draw in the registration marks through the slots.
-Cut the image including the surrounding marks out and place it on the mat (general orientation is important, location is not)
-Manually detect registration marks and cut. That's it!
I'm sharing the files that already has the SD registration marks, and the Cameo registration marks for a small image if you want to try this with your own stamp.