I have a neighbours daughters bike to fix at the moment. The freehub is totally seized. I've removed the freehub from the hub itself, but can't identify it nor have I see any like it. It doesn't have a separate locking screw and screws into the hub itself.
It looks similar to a DMR, Halo, or Sun freehub but it's only a cheap hub. The one that looks closest so far is the DMR. Yet the DMR has what looks like an aluminium bit at the end of the thread:
Pictures of the freehub are here: http://imgur.com/a/V11ef#0