Smicha I've found the best way to do this is drag and drop your mesh/item and disregard the octane errors. Then to copy and paste your material across including the Octane override, simply save the shader for that mesh item as a preset (works with shader hierarchy's also) then import that preset into your new scene and it should all work.
I can elaborate on this if you need, let me know.
Cheers,
dino.