Speak to amigakit. If they are supplying the kickswitcher I am sure they will supply you with the info for the newer (lol, not as old) roms.
They do say "Compatible with Kickstart 1.2, 1.3, 2.0, 2.04, 2.05, 3.1 (for A500/A2000)"
But I am guessing you will need to do the whatever mods are required for your older A500 as if you were you to insert the rom directly into the MB.
Gertsy