Chad,
in post 241 you can hopefully see what I mean, I hope "sponge" is the right word for the material []
As there are no wood inside for the horns, I simply insert some pieces of "sponge" inside to create a "cavity" where the horns will be sitting. This cavity is filled with epoxy, and the horns inserted. This will create a block of epoxy inside, "simulating" the wood that should have been there.
The epoxy then has contact with the upper and lower skin and the spars inside.
Only thing to careful about, is that there is enough glue inside, some of it will go into the sponge, so after a few minutes (before inserting the horns) I add some more, until I'm sure the cavity is completely filled.
I hope this makes sense, I could have explained it much better in Danish, but that would probably not work very well