ipv6 bridge over gif over tunnel

Hi,

I am trying to build an experimental system that connect 
an IPv6 route with the terminal via IPv4 network.

The network architecture is as follows:

 [IPv6 router]
     |
     | (IPv6)
     |
 [Open BSD bridge machine with PPPoE client and gif]
     |
     | (IPv4)
     |
 [PPPoE end point] 
     |
 [IPv4 router] 
     |
     | (IPv4)
     |
 [Open BSD bridge machine with gif]
     |
     | (IPv4)
     |
 [IPv6 terminal]  

At this moment, IPv6 terminal can send/receive ICMPv6 packet
to/from IPv6 router by using of 'ping6' without -s option.  
With '-s 1600', ICMPv6 packets are fragmented and 
reached IPv6 router, however reply of IPv6 router will not
be reached IPv6 terminal.  I think that PPPoE endpoint machine
drops fragmented packets .  Bridge implementation seems to fragment
packets correctly, but PPP implementatin seems bad.

Does anyone know how to solove this problem or any pointers on this matter?
Thank you in advance

Regards,
Hideki Yamamoto

-----------------------------------------------------------------
Hideki YAMAMOTO 		     |
Broadband Media Solutions Department | E-mail: [email protected]
Broadband Media Company		     | Tel: +81-48-420-7012
Oki Electric Industry Co., Ltd.      | FAX: +81-48-420-7016