I can't imagine a young snake not taking a live mouse. After bringing him home, I would wait at least a week or even two weeks to feed him (no handling either). This way he will get used to his new home and will not be stressed. After the first week he'll get used to the new enviroment and should get hungry. If you have a proper setup and don't bother him I'm betting he nails the mouse.

Also, I don't want to start a debate between live vs. frozen feeders but there are many people who would give anything for their BP to take a frozen feeder. Just think this over before tossing in a live mouse