Hi:
I had the same problem with a Honda CR250 '93 (but I do not know your model, so check if they are alike) the solution was to put something solid (like a piece of pipe big enough for the bolt to fit in) between the bike and a wall (or floor) to make sure that there is no possibility of the bike to move when you hammer it.
Then -although it may sound brutal- a sharp blow with a hammer and a cilindrical punch is what will take it out.
Like stated before, disconnect the rear shock absorber.
Hope this helps, good luck. :)