How to get IPv4 nodes in IPv6-over-IPv4 tunnel

[yjchui@ms.chttl.com.tw (Yann-Ju Chu)]

Hi,
        If I want to trace the IPv6 routers in the path, I can use traceroute(v6). However, If there is tunnel built in the path, the tool can not find any information. Is there any means (or protocol) to find any tunnel in a v6 path and the IPv4 routers in the tunnel?
                                        Chu