What is the correct way to overide hal defaults?

[Micha Feigin <michf@post.tau.ac.il>]

I want to change the default settings for my synaptic touchpad in X. I tried
changing /usr/share/hal/fdi/policy/20thirdparty/11-x11-synaptics.fdi but it
keeps getting written over during upgrades. Is there a better way to do this so
it won't get erased every time?

Thanks