Block Base: "Leaves" is still solid

I have a leaf textures set that is transparent (tested with normal block base and the transparent box checked), I read that you have to have the block base set to "leaves" to allow them to decay properly when there is no log block present. They decay like normal, BUT the leaves are no longer transparent. Is there some other way to make sure they go back to being transparent while keeping the block base set to "leaves"?