1220? I am pretty sure the minimal IPv6 MTU is 1280 and that below it
fragmentation should be handled by the medium that transports packets
smaller than that.... Can you enlighten me >> Bill? 
Please correct me if I'm wrong, but last I heard IPv6 routers do not do
fragmentation...it's up to the IPv6 end hosts to properly determine the path
MTU.
Thanks...
Vyto