WII dvd drive has been proven to work on a GC...and WKF passthru works even with a GC dvd drive connected....
so why wouldnt a Wii dvd drive work in passthru??
go to gc-forever.com
i have a sale thread there with a lot info on the development...
also if you are still wanting to use a wii drive on the GC, then just plug in the ffc cable from the wii drive to the WKF as normal....
the little insert adapter is only if you want to use the GC dvd drive...