I connect the simpliest black/white texture to a surface Shader´s Out Transparency. I assign it to an object. My Thumbnail in Hypershade looks just like what I want - I even get a nice transparency in the Viewport. But there´s no transparency in the rendered object. With a blinn or lambert, that works just fine.
What´s the difference between “Out Transparency” and “Transparency”? Also I realise that if I attempt to make a connection via Hypershade, in case of the surface shader Hypershade only offers a displacement connection. When I drop it on a blinn shader, I get a huge list of possible connections.