Apologies for resurrecting this older post. But you said you were able to apply vanilla textures to new objects? How have you been able to do that?
I am trying to create a new block, Corner Bars, to go with the iron bars but I have not been able to determine how to apply the iron bars texture to my new block. I can create a custom texture and apply it and it appears in game, but I cannot make it use the iron bars texture.
Any hints?