I decided to create my own Raspberry holder for the K8400 printer, because i want a easy access to hdmi-, usb-, network-, etc. ports. Also the micro sd can easily changed from the front of the printer. Mounting the Pi overhead does not fit these requirements for me. A nice feature is the Start/ Shutdown button with status LED. Link for the python script in the instructions. printed with 25% infill, 0.3mm layer for test print (0.2mm better) sliced with cura screw holes about 2mm (fits screws i found in the basement about 2.3x9.5mm). You can also drill it with 2.5 - 3mm to fit your screws. mount the holder with screws or with zipties like i did (look at the pictures). You have not to drill some holes in the bottom plate of the printer. The Manual for the Power-button i found here: http://www.forum-raspberrypi.de/Thread-tutorial-hoch-und-runterfahren-mittels-taster-incl-status-led