Screws in rollerski bindings

Hi,

I switched bindings on my V2s from Profil to NNN. The front three
wholes matched perfectly. However, after a couple of hours on rough
pavement I noticed that the front-most screw starts to come loose.
I've tightened it up a couple of times, but this only works for a
little while. I don't want to make the wholes bigger so I wouldn't
want to wrap the srews in anything. Maybe there is a way to secure the
scews from the top? I'm sure others had this problem since aluminum
shafts have so much less material to hold on to than regular skis. Any
ideas?

Thanks!

Sorry for the double - there was a server error that said first
message did not go through.