Lighttpd team roll out a prerelease of 1.5 r2294, get it here(http://blog.lighttpd.net/articles/2008/08/20/new-prereleases-1-4-20-r2294-and-1-5-r2294). I modified mod_extforward to make it work with it (some constants changed since last prerelease).
orz to the author of mod_extforward, great kxn.
see att for patch.