Vinciane:
If you look closely, on the LP=1 pedals yos see what appears to be or holes, or slots to fix the pedals to the piano:
If that holes/slots match the height of the horizontal beam on the DGX, you're done:
You can put some screws for fixing it from the back (pedals) to the front (piano spar) without making the screws to pass thru, so you don't see the screws on the pront side of the piano.
If the LP-1 holes dont match the height of the SGX horizontal spar, all is not lost, you can put an intermediate (white in this case) , small wooden plate, that on one side (back) fix the LP-1 pedals to the plate, and on the other side (front), fix the wooden plate , with the back side of the piano beam (without making pass-thru holes) so will look like an original part pf the piano.
Something like that (sorry for my drawing skills) i hope you understand my idea:
Red = Wood intermediate plate (maybe around 3/4" inch or 20mm should be enough)
Green = Back plate to fix the pedals
Blue = Front side fixed to the piano horiz beam.
I think that should make it work flawlessly