I'm glad my comment helps somebody who needed.
1.FX and FXA both have the same B4-mount. I have FXA also.
2.Putting a camera on B4-EF mount adapter directly will configure Direct Projection system. This will project small image circle that is not enough to fill full frame sensor. Direct Projection configuration will suit for 1" sensor like Nikon 1 series.
For full frame sensor will be needed another configuration.