First of all "Phillips" screwdriver does not work.
You need to make "pozidrive" (spelling?) tip.

Take a Phillips tip #P2 and grind the end of to fit the screw.
Then get a l shape screwdriver to get to the screw under a lock on Salomon
binding and also grind about 3mm of the tip.

If you need to install new binding, you need to know "balance point"
of that ski or replicate the same from old ski, if it is perfect for you.