thejimmyrigger

Scott,
Prop the branch upright, thin out the foliage put it in some soil with rooting hormone, place it out of direct sunlight and we'll see what happens. I'm not experienced with Jpn. Maple, so I'm not sure on its successes with rooting. But it's worth a shot.

Also try these guys:

Gardenweb Maples


GardenWeb Trees

Good luck
jim