Either mod the game so that the block you want doesn't trigger culling, or else disable culling on everything else and learn to love 0.001 fps gameplay.
I suggest instead planning your model around the idea that a full block has to in fact be a full block. Less creative options, but also less hassle all around.
Sorry to be the bearer of bad news.
That's fine, I didn't expect good news. I just wanted to make sure no one else had found something amazing that would let it be possible.
I already tried to turn of culling of every block.. ehm *cough* NOP. just nop.
Even if its bad news, its informative, you still saved me hours of searching around, so thanks a lot!