IPv6 routing

Hello,

I've been allocated a /64 IPv6 subnet by my provider (Free, for those who 
might have had/solved the same problem), but I'm having some trouble setting 
it up. The situation is as follows: the ADSL modem (addres <subnet>::1) is 
connected to a router, which is connected to a local network.

I found a solution for Gentoo here: http://gentoo-wiki.com/IPV6_And_Freebox , 
but I've no idea on how to set up a proxy NDP for NetBSD (it doesn't work 
without one, I've tried - and using ndp -s works only very partially: I can 
only ping the 'external' router address, but not the ADSL modem or anything 
further than that)

I've also tried setting up the 'external' interface as <subnet>::2/126, and 
the 'internal' interface as <subnet>:8000::1/65, so they are in distinct 
networks, but this not only wreaks havoc with autoconfiguration, it doesn't 
work either (I can still only ping the external IPv6 address of the router).

I've found some other solutions around (IPv6-only bridges? using IPF with to 
and dup-to?) but I'm not sure how to configure this practically.

So: does someone have any tips on how to set this up on NetBSD? I'd be very 
grateful!

Kind regards,

  Jaap Boender