You do this wrong. In Devs/kickstarts directory you need at least these files. And most of WHDLoad games which new kickstart files should work.
Code:
Kick40068.a1200
Kick40068.a4000
Kick33180.a500
Kick34005.a500
Kick33180.a500.rtb
Kick34005.a500.rtb
Kick40068.a1200.rtb
Kick40068.a4000.rtb
On net you should be able to find these files in correct version and *.rtb files can be downloaded from Aminet. See example information on readme of some game which need any kickstart Image. For example this one:
http://whdload.de/games/Franko.html