The brake and sprocket hubs are just slid onto the axle on a spline pattern, the axle nut is what holds it on. Sounds like you need some heat applied to the hub to loosen it up.
Don't think you will get a answer here. This post is a bit old.hey got the exact same problem on my mates 700, how did you remove it in the end? we have knocked the shit outta it but it seems to be stuck solid, sledgehammer is the next stop unless theres any other way.