Or more easily if you are on windows 7 go
ctrl pannel
devices and printers
Then right click on your joystick e.g. Cyborg X
Game controller settings
Properties
Deadzones
Find your Z Axis details
You will have 4 markers you can slide around to customise your axis
For ARMA 2 you want to first of all right click and ensure the deadzones are not linked
Then drag all 3 of the left most markers to the far left and right most to the far right.
You can test what this does on the TEST page after applying.
Basically to begin with the slider will go up very quickly with minimal movement until halfway, where it will slow down and cover the remaining axis very slowly.
It isnt perfect there is effectively a small deadzone at the beginning of the throttle to about 5-10% throttle, but it is effective, requires very little mucking around with programs and has absolutely zero risk of downloading the wrong thing and being riddled with trojans.
Also if you play other games you must remember to set it back to normal (clear deadzone).
Something similar can be done on XP however it is slightly more complicated.