I've manually constructed a rectangle (from VertexPositionNormalTextures) to try to make billboards using two methods. 

In the first method I layed the vertices out in clockwise order, drawing the rectangle with effect.World = Matrix.Identity shows the rectangle but drawing the rectangle with effect.World = Matrix.CreateBillboard() shows nothing.

In the second method I constructed the rectangle with vertices in counterclockwise order, drawing the rectangle with effect.World = Matrix.Identity culls it out, but drawing it with effect.World = Matrix.CreateBillboard() shows it like a billboard should be (always facing camera etc.)

Toying with different device.RenderState.CullModes it seems to me CreateBillboard automatically rotates the applied object PI radians around the "Camera Up" vector.  Anyone know more about this, or somewhere else I might be going wrong?

Thanks in advance