Yam pizza - ideas requested

To mark the completion of their study of the literature of the Igbo people of Nigeria, my son's Literature class is having a Happy Yam Day. He has requested that I make yam pizza for him to take in.

OK, so after doing some research on yams (not to be confused with sweet potatos for we USians), both on the Internet and at my local international foods store, I find that the Ghana yam is probably the closest thing to the Nigerian yam available to me.

I also find that raw yams are toxic, that they must be thoroughly cooked to destroy the not-so-nice chemicals, and that the water they are cooked in must be discarded. Good thing I found out that last as I had first intended to use the water as if it were potato water!

So, any thoughts from the breadosphere on how to incorporate yams into pizza? My first thought is to use them as an additive to the dough in the same way I use potatos: boil thoroughly, mash with a bit of oil, and add to dough ingredients.

However, my son would like something more identifiably "yam-like". My next thought was to boil until just soft, slice, brush with olive oil, broil until a bit brown, then use as a topping. [I was going to just slice and broil until I read about the toxicity problem] Not sure how that would work though.

Any other thoughts? Can any of our Asian readers comment? I know that the yams in Asia are somewhat different than West African yams, but the principles should be the same I think.

Thanks for your help!

sPh