Omar,
Tried to check the screws on my 24-70. I found there are three openings with three correspnding screws under the focus ring, just as you descibed. You need to move both the focus and zoom rings to get them to line up right.
But I couldn't move the screws - seems like they were exceptionally tight. That said, I was afraid to really torque them (for obvious reasons).
The screws are small and appear to be surrounded by a brass ring that is slightly raised and looks like it has a slots for a slotted screwdriver on them. Is this different than what's on the 24-105? I wondered if the center locking screw perhaps needs to be loosened to allow you to turn the brass ring....
Anyone try this on a 24-70? Minor slipperiness on mine, couldn't really even call it "creep"....