Unity doesn't build _DirectToRift.exe

I'm trying to add the unity package to an existing project. I've tried both unity 4 and 5 and I've got 'optimize for rift' checked but it doesn't create the _DirectToRift.exe.

The .exe that is created does have the oculus rift 2 views and responds to rotating the rift. The image is just never shown on the rift itself.

Any ideas why unity would build _DirectToRift.exe? So far google searched have turned up empty for me.