If the bolt is sticking out at all, just back it out with a pair of pliers. Otherwise, you might try this: first, drill a hole into it with a bit smaller than the bolt itself; second, get a bit slightly bigger than the one you just used, put your drill on reverse, and now try backing it out while applying a good amount of pressure to the drill. You might also be able to shove something like a very small phillips screwdriver in that hole you drilled to back the bolt out.
If the bolt din't snap clean, you might have to try grabbing the jagged edge with a pair of needle nose or something like that to carefully twist it out. Careful not to bugger up the threads in the case.
Your bolt should be an m6-1 and maybe 75 or 90 long, which you should be able to get at a hardware store. If not, I'm sure you could get one from service honda.
-John