I've never made soap using honeycomb before, but I have tried eating honeycomb once. I think I remember it being vey waxy. I don't see why you couldn't use it in your soap by melting a little bit of it down with your oils before adding the lye, for I know of other soapers melting and adding beeswax to to their batches to achieve a harder bar with great success. From what I remember reading, though, they don't use too much of it because too much can kill lather.
I make a soap with beeswax and honey, and would like to use the honeycomb. I'm pretty sure it's beeswax. I would have to drain the honey from it first to get an accurate weight, I suppose. Looks like I may have to be the pioneer!
Honey comb IS made out of beeswax, by bees of course It melts at around 146° F. When you melt honey comb you get mostly pure beeswax and some amount of "slumgum" which is mostly propolis with some other gunk. Combs sold as comb honey are pretty much pure beeswax.