ok heres an idea i have gotten based on my reading on respawning vehicles. keep in mind, i dont know if it works, youll have to test it.. hope it does
ok, put your NPC in, then give it a key of "count" (remember no "") then a value of -1 this makes it respawn. Then give it a targetname. Also, give it a delay of whatever probably 5 (for 5 seconds) so it will spawn 5 seconds after your NPC dies.
Then for the worldspawn, give it a key of Spawnscript then a value of wherever and what ever your script is. Then the worldspawn should run that script when the map starts.
make the script, just put in it, USE and then the targetname you gave for your NPC. Save compile... your done
hopefully!!! The use command is like a trigger, and since your npc has the targetname it uses, it should trigger it to spawn...
That should do it..... :-\