Mike, we changed our mattress to a Sleep Compfort and did it ourselves. The key is to space the "fiberboards" above the frame to allow the pump to lay directly under the mattress & your fiberboards.
Our bed frame had 2 - plywood boards for support and not fiberboards as you've stated. However, my procedure should still work. I added 1 X 2 pine "furring strips" to the frame (typically used to space drywall out away from a wall). The boards were laid on their side (2" side). The boards are slightly wider than the frame so I allowed the extra to overhang inside the frame. I used the appropriate length flat head sheet metal screws (size?). NOTE: You do NOT need to build a picture frame out of the strips ... just enough support for your fiberboards to screw back into place.
I laid the pump unit in an available space towards the head of the bed and slightly right of center (facing). As I recall, there's a cavity area that was pretty convenient and didn't interfere with slide operation. I brought the power cord over to the right (facing) to be plugged into the A/C outlet next to the bed. I'm pretty sure I drilled holes or cut out a space in the right side plywood (your fiberboard) to bring the air lines & A/C cord up through the plywood (your fiberboard). Keep the air lines as close to the top and center as possible to not interfere with the bladders.
You'll find that the end of the bed will now "jam" a little more in & under the vanity cabinet because of the new bed heigth. You'll see a slight impression in the bedspread when both slides are closed but I've not seen any real problem issues thus far. Both slides close without hesitation. We've had ours for 2 - years.
That's the best I can remember of the procedure. Let me know if you have any questions or concerns. And, you can always email me at firstname.lastname@example.org
One more issue - we've noticed that the pump (via the remote) registers different pressure at times and needs to be checked each time we go to bed. I've had it lose air which caused my back to hurt until I determined the problem. I would suspect a leak but I've had it register "100" (maximum) after moving to a new campsite just as much as registering too low. I suspect that differences in the quality of A/C between the Inverter, Generator, and shore power may be causing the issue. Please share your experinece.