Gotta make sure you grind off or drill off the original rivet head and not the end which was rivetted, since the rivetted end will have flared during the rivetting process and it's a bugg*r to try and pull this through the plastic and you also risk damaging the holes for the hub.
Drilling off the original rivet heads means you're pulling the wider rivetted end away from the hub as opposed to through it.
Does that make sense?